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390437fc6d
ConstRules. Remove the casting rules from ConstRules and subclasses. This cleans up ConstantFolding significantly. Passes all tests. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32671 91177308-0d34-0410-b5e6-96231b3b80d8
1568 lines
65 KiB
C++
1568 lines
65 KiB
C++
//===- ConstantFolding.cpp - LLVM constant folder -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by the LLVM research group and is distributed under
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// the University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements folding of constants for LLVM. This implements the
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// (internal) ConstantFolding.h interface, which is used by the
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// ConstantExpr::get* methods to automatically fold constants when possible.
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//
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// The current constant folding implementation is implemented in two pieces: the
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// template-based folder for simple primitive constants like ConstantInt, and
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// the special case hackery that we use to symbolically evaluate expressions
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// that use ConstantExprs.
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//
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//===----------------------------------------------------------------------===//
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#include "ConstantFolding.h"
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#include "llvm/Constants.h"
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#include "llvm/Instructions.h"
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#include "llvm/DerivedTypes.h"
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#include "llvm/Function.h"
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#include "llvm/Support/Compiler.h"
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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#include "llvm/Support/ManagedStatic.h"
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#include "llvm/Support/MathExtras.h"
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#include <limits>
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using namespace llvm;
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namespace {
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struct VISIBILITY_HIDDEN ConstRules {
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ConstRules() {}
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virtual ~ConstRules() {}
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// Binary Operators...
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virtual Constant *add(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *sub(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *mul(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *urem(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *srem(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *frem(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *udiv(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *sdiv(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *fdiv(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *op_and(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *op_or (const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *op_xor(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *shl(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *lshr(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *ashr(const Constant *V1, const Constant *V2) const = 0;
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virtual Constant *lessthan(const Constant *V1, const Constant *V2) const =0;
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virtual Constant *equalto(const Constant *V1, const Constant *V2) const = 0;
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// ConstRules::get - Return an instance of ConstRules for the specified
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// constant operands.
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//
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static ConstRules &get(const Constant *V1, const Constant *V2);
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private:
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ConstRules(const ConstRules &); // Do not implement
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ConstRules &operator=(const ConstRules &); // Do not implement
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};
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}
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//===----------------------------------------------------------------------===//
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// TemplateRules Class
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//===----------------------------------------------------------------------===//
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//
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// TemplateRules - Implement a subclass of ConstRules that provides all
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// operations as noops. All other rules classes inherit from this class so
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// that if functionality is needed in the future, it can simply be added here
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// and to ConstRules without changing anything else...
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//
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// This class also provides subclasses with typesafe implementations of methods
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// so that don't have to do type casting.
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//
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namespace {
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template<class ArgType, class SubClassName>
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class VISIBILITY_HIDDEN TemplateRules : public ConstRules {
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//===--------------------------------------------------------------------===//
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// Redirecting functions that cast to the appropriate types
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//===--------------------------------------------------------------------===//
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virtual Constant *add(const Constant *V1, const Constant *V2) const {
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return SubClassName::Add((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *sub(const Constant *V1, const Constant *V2) const {
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return SubClassName::Sub((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *mul(const Constant *V1, const Constant *V2) const {
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return SubClassName::Mul((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *udiv(const Constant *V1, const Constant *V2) const {
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return SubClassName::UDiv((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *sdiv(const Constant *V1, const Constant *V2) const {
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return SubClassName::SDiv((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *fdiv(const Constant *V1, const Constant *V2) const {
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return SubClassName::FDiv((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *urem(const Constant *V1, const Constant *V2) const {
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return SubClassName::URem((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *srem(const Constant *V1, const Constant *V2) const {
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return SubClassName::SRem((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *frem(const Constant *V1, const Constant *V2) const {
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return SubClassName::FRem((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *op_and(const Constant *V1, const Constant *V2) const {
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return SubClassName::And((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *op_or(const Constant *V1, const Constant *V2) const {
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return SubClassName::Or((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *op_xor(const Constant *V1, const Constant *V2) const {
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return SubClassName::Xor((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *shl(const Constant *V1, const Constant *V2) const {
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return SubClassName::Shl((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *lshr(const Constant *V1, const Constant *V2) const {
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return SubClassName::LShr((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *ashr(const Constant *V1, const Constant *V2) const {
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return SubClassName::AShr((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *lessthan(const Constant *V1, const Constant *V2) const {
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return SubClassName::LessThan((const ArgType *)V1, (const ArgType *)V2);
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}
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virtual Constant *equalto(const Constant *V1, const Constant *V2) const {
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return SubClassName::EqualTo((const ArgType *)V1, (const ArgType *)V2);
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}
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//===--------------------------------------------------------------------===//
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// Default "noop" implementations
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//===--------------------------------------------------------------------===//
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static Constant *Add (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *Sub (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *Mul (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *SDiv(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *UDiv(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *FDiv(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *URem(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *SRem(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *FRem(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *And (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *Or (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *Xor (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *Shl (const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *LShr(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *AShr(const ArgType *V1, const ArgType *V2) { return 0; }
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static Constant *LessThan(const ArgType *V1, const ArgType *V2) {
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return 0;
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}
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static Constant *EqualTo(const ArgType *V1, const ArgType *V2) {
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return 0;
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}
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public:
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virtual ~TemplateRules() {}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// EmptyRules Class
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//===----------------------------------------------------------------------===//
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//
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// EmptyRules provides a concrete base class of ConstRules that does nothing
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//
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namespace {
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struct VISIBILITY_HIDDEN EmptyRules
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: public TemplateRules<Constant, EmptyRules> {
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static Constant *EqualTo(const Constant *V1, const Constant *V2) {
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if (V1 == V2) return ConstantBool::getTrue();
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return 0;
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}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// BoolRules Class
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//===----------------------------------------------------------------------===//
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//
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// BoolRules provides a concrete base class of ConstRules for the 'bool' type.
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//
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namespace {
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struct VISIBILITY_HIDDEN BoolRules
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: public TemplateRules<ConstantBool, BoolRules> {
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static Constant *LessThan(const ConstantBool *V1, const ConstantBool *V2) {
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return ConstantBool::get(V1->getValue() < V2->getValue());
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}
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static Constant *EqualTo(const Constant *V1, const Constant *V2) {
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return ConstantBool::get(V1 == V2);
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}
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static Constant *And(const ConstantBool *V1, const ConstantBool *V2) {
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return ConstantBool::get(V1->getValue() & V2->getValue());
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}
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static Constant *Or(const ConstantBool *V1, const ConstantBool *V2) {
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return ConstantBool::get(V1->getValue() | V2->getValue());
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}
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static Constant *Xor(const ConstantBool *V1, const ConstantBool *V2) {
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return ConstantBool::get(V1->getValue() ^ V2->getValue());
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}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// NullPointerRules Class
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//===----------------------------------------------------------------------===//
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//
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// NullPointerRules provides a concrete base class of ConstRules for null
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// pointers.
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//
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namespace {
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struct VISIBILITY_HIDDEN NullPointerRules
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: public TemplateRules<ConstantPointerNull, NullPointerRules> {
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static Constant *EqualTo(const Constant *V1, const Constant *V2) {
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return ConstantBool::getTrue(); // Null pointers are always equal
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}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// ConstantPackedRules Class
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//===----------------------------------------------------------------------===//
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/// DoVectorOp - Given two packed constants and a function pointer, apply the
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/// function pointer to each element pair, producing a new ConstantPacked
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/// constant.
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static Constant *EvalVectorOp(const ConstantPacked *V1,
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const ConstantPacked *V2,
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Constant *(*FP)(Constant*, Constant*)) {
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std::vector<Constant*> Res;
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for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i)
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Res.push_back(FP(const_cast<Constant*>(V1->getOperand(i)),
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const_cast<Constant*>(V2->getOperand(i))));
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return ConstantPacked::get(Res);
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}
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/// PackedTypeRules provides a concrete base class of ConstRules for
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/// ConstantPacked operands.
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///
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namespace {
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struct VISIBILITY_HIDDEN ConstantPackedRules
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: public TemplateRules<ConstantPacked, ConstantPackedRules> {
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static Constant *Add(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getAdd);
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}
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static Constant *Sub(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getSub);
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}
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static Constant *Mul(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getMul);
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}
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static Constant *UDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getUDiv);
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}
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static Constant *SDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getSDiv);
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}
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static Constant *FDiv(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getFDiv);
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}
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static Constant *URem(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getURem);
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}
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static Constant *SRem(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getSRem);
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}
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static Constant *FRem(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getFRem);
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}
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static Constant *And(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getAnd);
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}
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static Constant *Or (const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getOr);
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}
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static Constant *Xor(const ConstantPacked *V1, const ConstantPacked *V2) {
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return EvalVectorOp(V1, V2, ConstantExpr::getXor);
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}
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static Constant *LessThan(const ConstantPacked *V1, const ConstantPacked *V2){
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return 0;
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}
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static Constant *EqualTo(const ConstantPacked *V1, const ConstantPacked *V2) {
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for (unsigned i = 0, e = V1->getNumOperands(); i != e; ++i) {
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Constant *C =
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ConstantExpr::getSetEQ(const_cast<Constant*>(V1->getOperand(i)),
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const_cast<Constant*>(V2->getOperand(i)));
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if (ConstantBool *CB = dyn_cast<ConstantBool>(C))
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return CB;
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}
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// Otherwise, could not decide from any element pairs.
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return 0;
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}
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// GeneralPackedRules Class
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//===----------------------------------------------------------------------===//
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/// GeneralPackedRules provides a concrete base class of ConstRules for
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/// PackedType operands, where both operands are not ConstantPacked. The usual
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/// cause for this is that one operand is a ConstantAggregateZero.
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///
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namespace {
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struct VISIBILITY_HIDDEN GeneralPackedRules
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: public TemplateRules<Constant, GeneralPackedRules> {
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};
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} // end anonymous namespace
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//===----------------------------------------------------------------------===//
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// DirectIntRules Class
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//===----------------------------------------------------------------------===//
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//
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// DirectIntRules provides implementations of functions that are valid on
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// integer types, but not all types in general.
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//
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namespace {
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template <class BuiltinType, Type **Ty>
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struct VISIBILITY_HIDDEN DirectIntRules
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: public TemplateRules<ConstantInt, DirectIntRules<BuiltinType, Ty> > {
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static Constant *Add(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R = (BuiltinType)V1->getZExtValue() +
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(BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *Sub(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R = (BuiltinType)V1->getZExtValue() -
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(BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *Mul(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R = (BuiltinType)V1->getZExtValue() *
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(BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *LessThan(const ConstantInt *V1, const ConstantInt *V2) {
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bool R = (BuiltinType)V1->getZExtValue() < (BuiltinType)V2->getZExtValue();
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return ConstantBool::get(R);
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}
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static Constant *EqualTo(const ConstantInt *V1, const ConstantInt *V2) {
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bool R = (BuiltinType)V1->getZExtValue() == (BuiltinType)V2->getZExtValue();
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return ConstantBool::get(R);
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}
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static Constant *UDiv(const ConstantInt *V1, const ConstantInt *V2) {
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if (V2->isNullValue()) // X / 0
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return 0;
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BuiltinType R = (BuiltinType)(V1->getZExtValue() / V2->getZExtValue());
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return ConstantInt::get(*Ty, R);
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}
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static Constant *SDiv(const ConstantInt *V1, const ConstantInt *V2) {
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if (V2->isNullValue()) // X / 0
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return 0;
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if (V2->isAllOnesValue() && // MIN_INT / -1
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(BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue())
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return 0;
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BuiltinType R = (BuiltinType)(V1->getSExtValue() / V2->getSExtValue());
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return ConstantInt::get(*Ty, R);
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}
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static Constant *URem(const ConstantInt *V1,
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const ConstantInt *V2) {
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if (V2->isNullValue()) return 0; // X / 0
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BuiltinType R = (BuiltinType)(V1->getZExtValue() % V2->getZExtValue());
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return ConstantInt::get(*Ty, R);
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}
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static Constant *SRem(const ConstantInt *V1,
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const ConstantInt *V2) {
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if (V2->isNullValue()) return 0; // X % 0
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if (V2->isAllOnesValue() && // MIN_INT % -1
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(BuiltinType)V1->getSExtValue() == -(BuiltinType)V1->getSExtValue())
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return 0;
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BuiltinType R = (BuiltinType)(V1->getSExtValue() % V2->getSExtValue());
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return ConstantInt::get(*Ty, R);
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}
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static Constant *And(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R =
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(BuiltinType)V1->getZExtValue() & (BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *Or(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R =
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(BuiltinType)V1->getZExtValue() | (BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *Xor(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R =
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(BuiltinType)V1->getZExtValue() ^ (BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *Shl(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R =
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(BuiltinType)V1->getZExtValue() << (BuiltinType)V2->getZExtValue();
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return ConstantInt::get(*Ty, R);
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}
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static Constant *LShr(const ConstantInt *V1, const ConstantInt *V2) {
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BuiltinType R = BuiltinType(V1->getZExtValue() >> V2->getZExtValue());
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return ConstantInt::get(*Ty, R);
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}
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static Constant *AShr(const ConstantInt *V1, const ConstantInt *V2) {
|
|
BuiltinType R = BuiltinType(V1->getSExtValue() >> V2->getZExtValue());
|
|
return ConstantInt::get(*Ty, R);
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// DirectFPRules Class
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
/// DirectFPRules provides implementations of functions that are valid on
|
|
/// floating point types, but not all types in general.
|
|
///
|
|
namespace {
|
|
template <class BuiltinType, Type **Ty>
|
|
struct VISIBILITY_HIDDEN DirectFPRules
|
|
: public TemplateRules<ConstantFP, DirectFPRules<BuiltinType, Ty> > {
|
|
|
|
static Constant *Add(const ConstantFP *V1, const ConstantFP *V2) {
|
|
BuiltinType R = (BuiltinType)V1->getValue() +
|
|
(BuiltinType)V2->getValue();
|
|
return ConstantFP::get(*Ty, R);
|
|
}
|
|
|
|
static Constant *Sub(const ConstantFP *V1, const ConstantFP *V2) {
|
|
BuiltinType R = (BuiltinType)V1->getValue() - (BuiltinType)V2->getValue();
|
|
return ConstantFP::get(*Ty, R);
|
|
}
|
|
|
|
static Constant *Mul(const ConstantFP *V1, const ConstantFP *V2) {
|
|
BuiltinType R = (BuiltinType)V1->getValue() * (BuiltinType)V2->getValue();
|
|
return ConstantFP::get(*Ty, R);
|
|
}
|
|
|
|
static Constant *LessThan(const ConstantFP *V1, const ConstantFP *V2) {
|
|
bool R = (BuiltinType)V1->getValue() < (BuiltinType)V2->getValue();
|
|
return ConstantBool::get(R);
|
|
}
|
|
|
|
static Constant *EqualTo(const ConstantFP *V1, const ConstantFP *V2) {
|
|
bool R = (BuiltinType)V1->getValue() == (BuiltinType)V2->getValue();
|
|
return ConstantBool::get(R);
|
|
}
|
|
|
|
static Constant *FRem(const ConstantFP *V1, const ConstantFP *V2) {
|
|
if (V2->isNullValue()) return 0;
|
|
BuiltinType Result = std::fmod((BuiltinType)V1->getValue(),
|
|
(BuiltinType)V2->getValue());
|
|
return ConstantFP::get(*Ty, Result);
|
|
}
|
|
static Constant *FDiv(const ConstantFP *V1, const ConstantFP *V2) {
|
|
BuiltinType inf = std::numeric_limits<BuiltinType>::infinity();
|
|
if (V2->isExactlyValue(0.0)) return ConstantFP::get(*Ty, inf);
|
|
if (V2->isExactlyValue(-0.0)) return ConstantFP::get(*Ty, -inf);
|
|
BuiltinType R = (BuiltinType)V1->getValue() / (BuiltinType)V2->getValue();
|
|
return ConstantFP::get(*Ty, R);
|
|
}
|
|
};
|
|
} // end anonymous namespace
|
|
|
|
static ManagedStatic<EmptyRules> EmptyR;
|
|
static ManagedStatic<BoolRules> BoolR;
|
|
static ManagedStatic<NullPointerRules> NullPointerR;
|
|
static ManagedStatic<ConstantPackedRules> ConstantPackedR;
|
|
static ManagedStatic<GeneralPackedRules> GeneralPackedR;
|
|
static ManagedStatic<DirectIntRules<signed char , &Type::SByteTy> > SByteR;
|
|
static ManagedStatic<DirectIntRules<unsigned char , &Type::UByteTy> > UByteR;
|
|
static ManagedStatic<DirectIntRules<signed short , &Type::ShortTy> > ShortR;
|
|
static ManagedStatic<DirectIntRules<unsigned short, &Type::UShortTy> > UShortR;
|
|
static ManagedStatic<DirectIntRules<signed int , &Type::IntTy> > IntR;
|
|
static ManagedStatic<DirectIntRules<unsigned int , &Type::UIntTy> > UIntR;
|
|
static ManagedStatic<DirectIntRules<int64_t , &Type::LongTy> > LongR;
|
|
static ManagedStatic<DirectIntRules<uint64_t , &Type::ULongTy> > ULongR;
|
|
static ManagedStatic<DirectFPRules <float , &Type::FloatTy> > FloatR;
|
|
static ManagedStatic<DirectFPRules <double , &Type::DoubleTy> > DoubleR;
|
|
|
|
/// ConstRules::get - This method returns the constant rules implementation that
|
|
/// implements the semantics of the two specified constants.
|
|
ConstRules &ConstRules::get(const Constant *V1, const Constant *V2) {
|
|
if (isa<ConstantExpr>(V1) || isa<ConstantExpr>(V2) ||
|
|
isa<GlobalValue>(V1) || isa<GlobalValue>(V2) ||
|
|
isa<UndefValue>(V1) || isa<UndefValue>(V2))
|
|
return *EmptyR;
|
|
|
|
switch (V1->getType()->getTypeID()) {
|
|
default: assert(0 && "Unknown value type for constant folding!");
|
|
case Type::BoolTyID: return *BoolR;
|
|
case Type::PointerTyID: return *NullPointerR;
|
|
case Type::SByteTyID: return *SByteR;
|
|
case Type::UByteTyID: return *UByteR;
|
|
case Type::ShortTyID: return *ShortR;
|
|
case Type::UShortTyID: return *UShortR;
|
|
case Type::IntTyID: return *IntR;
|
|
case Type::UIntTyID: return *UIntR;
|
|
case Type::LongTyID: return *LongR;
|
|
case Type::ULongTyID: return *ULongR;
|
|
case Type::FloatTyID: return *FloatR;
|
|
case Type::DoubleTyID: return *DoubleR;
|
|
case Type::PackedTyID:
|
|
if (isa<ConstantPacked>(V1) && isa<ConstantPacked>(V2))
|
|
return *ConstantPackedR;
|
|
return *GeneralPackedR; // Constant folding rules for ConstantAggregateZero.
|
|
}
|
|
}
|
|
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// ConstantFold*Instruction Implementations
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
/// CastConstantPacked - Convert the specified ConstantPacked node to the
|
|
/// specified packed type. At this point, we know that the elements of the
|
|
/// input packed constant are all simple integer or FP values.
|
|
static Constant *CastConstantPacked(ConstantPacked *CP,
|
|
const PackedType *DstTy) {
|
|
unsigned SrcNumElts = CP->getType()->getNumElements();
|
|
unsigned DstNumElts = DstTy->getNumElements();
|
|
const Type *SrcEltTy = CP->getType()->getElementType();
|
|
const Type *DstEltTy = DstTy->getElementType();
|
|
|
|
// If both vectors have the same number of elements (thus, the elements
|
|
// are the same size), perform the conversion now.
|
|
if (SrcNumElts == DstNumElts) {
|
|
std::vector<Constant*> Result;
|
|
|
|
// If the src and dest elements are both integers, or both floats, we can
|
|
// just BitCast each element because the elements are the same size.
|
|
if ((SrcEltTy->isIntegral() && DstEltTy->isIntegral()) ||
|
|
(SrcEltTy->isFloatingPoint() && DstEltTy->isFloatingPoint())) {
|
|
for (unsigned i = 0; i != SrcNumElts; ++i)
|
|
Result.push_back(
|
|
ConstantExpr::getBitCast(CP->getOperand(i), DstEltTy));
|
|
return ConstantPacked::get(Result);
|
|
}
|
|
|
|
// If this is an int-to-fp cast ..
|
|
if (SrcEltTy->isIntegral()) {
|
|
// Ensure that it is int-to-fp cast
|
|
assert(DstEltTy->isFloatingPoint());
|
|
if (DstEltTy->getTypeID() == Type::DoubleTyID) {
|
|
for (unsigned i = 0; i != SrcNumElts; ++i) {
|
|
double V =
|
|
BitsToDouble(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
|
|
Result.push_back(ConstantFP::get(Type::DoubleTy, V));
|
|
}
|
|
return ConstantPacked::get(Result);
|
|
}
|
|
assert(DstEltTy == Type::FloatTy && "Unknown fp type!");
|
|
for (unsigned i = 0; i != SrcNumElts; ++i) {
|
|
float V =
|
|
BitsToFloat(cast<ConstantInt>(CP->getOperand(i))->getZExtValue());
|
|
Result.push_back(ConstantFP::get(Type::FloatTy, V));
|
|
}
|
|
return ConstantPacked::get(Result);
|
|
}
|
|
|
|
// Otherwise, this is an fp-to-int cast.
|
|
assert(SrcEltTy->isFloatingPoint() && DstEltTy->isIntegral());
|
|
|
|
if (SrcEltTy->getTypeID() == Type::DoubleTyID) {
|
|
for (unsigned i = 0; i != SrcNumElts; ++i) {
|
|
uint64_t V =
|
|
DoubleToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
|
|
Constant *C = ConstantInt::get(Type::ULongTy, V);
|
|
Result.push_back(ConstantExpr::getBitCast(C, DstEltTy ));
|
|
}
|
|
return ConstantPacked::get(Result);
|
|
}
|
|
|
|
assert(SrcEltTy->getTypeID() == Type::FloatTyID);
|
|
for (unsigned i = 0; i != SrcNumElts; ++i) {
|
|
uint32_t V = FloatToBits(cast<ConstantFP>(CP->getOperand(i))->getValue());
|
|
Constant *C = ConstantInt::get(Type::UIntTy, V);
|
|
Result.push_back(ConstantExpr::getBitCast(C, DstEltTy));
|
|
}
|
|
return ConstantPacked::get(Result);
|
|
}
|
|
|
|
// Otherwise, this is a cast that changes element count and size. Handle
|
|
// casts which shrink the elements here.
|
|
|
|
// FIXME: We need to know endianness to do this!
|
|
|
|
return 0;
|
|
}
|
|
|
|
/// This function determines which opcode to use to fold two constant cast
|
|
/// expressions together. It uses CastInst::isEliminableCastPair to determine
|
|
/// the opcode. Consequently its just a wrapper around that function.
|
|
/// @Determine if it is valid to fold a cast of a cast
|
|
static unsigned
|
|
foldConstantCastPair(
|
|
unsigned opc, ///< opcode of the second cast constant expression
|
|
const ConstantExpr*Op, ///< the first cast constant expression
|
|
const Type *DstTy ///< desintation type of the first cast
|
|
) {
|
|
assert(Op && Op->isCast() && "Can't fold cast of cast without a cast!");
|
|
assert(DstTy && DstTy->isFirstClassType() && "Invalid cast destination type");
|
|
assert(CastInst::isCast(opc) && "Invalid cast opcode");
|
|
|
|
// The the types and opcodes for the two Cast constant expressions
|
|
const Type *SrcTy = Op->getOperand(0)->getType();
|
|
const Type *MidTy = Op->getType();
|
|
Instruction::CastOps firstOp = Instruction::CastOps(Op->getOpcode());
|
|
Instruction::CastOps secondOp = Instruction::CastOps(opc);
|
|
|
|
// Let CastInst::isEliminableCastPair do the heavy lifting.
|
|
return CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy, DstTy,
|
|
Type::ULongTy);
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldCastInstruction(unsigned opc, const Constant *V,
|
|
const Type *DestTy) {
|
|
const Type *SrcTy = V->getType();
|
|
|
|
if (isa<UndefValue>(V))
|
|
return UndefValue::get(DestTy);
|
|
|
|
// If the cast operand is a constant expression, there's a few things we can
|
|
// do to try to simplify it.
|
|
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
|
|
if (CE->isCast()) {
|
|
// Try hard to fold cast of cast because they are often eliminable.
|
|
if (unsigned newOpc = foldConstantCastPair(opc, CE, DestTy))
|
|
return ConstantExpr::getCast(newOpc, CE->getOperand(0), DestTy);
|
|
} else if (CE->getOpcode() == Instruction::GetElementPtr) {
|
|
// If all of the indexes in the GEP are null values, there is no pointer
|
|
// adjustment going on. We might as well cast the source pointer.
|
|
bool isAllNull = true;
|
|
for (unsigned i = 1, e = CE->getNumOperands(); i != e; ++i)
|
|
if (!CE->getOperand(i)->isNullValue()) {
|
|
isAllNull = false;
|
|
break;
|
|
}
|
|
if (isAllNull)
|
|
// This is casting one pointer type to another, always BitCast
|
|
return ConstantExpr::getPointerCast(CE->getOperand(0), DestTy);
|
|
}
|
|
}
|
|
|
|
// We actually have to do a cast now. Perform the cast according to the
|
|
// opcode specified.
|
|
switch (opc) {
|
|
case Instruction::FPTrunc:
|
|
case Instruction::FPExt:
|
|
return ConstantFP::get(DestTy, cast<ConstantFP>(V)->getValue());
|
|
case Instruction::FPToUI: {
|
|
double dVal = cast<ConstantFP>(V)->getValue();
|
|
uint64_t iVal = (uint64_t) dVal;
|
|
return ConstantIntegral::get(DestTy, iVal);
|
|
}
|
|
case Instruction::FPToSI: {
|
|
double dVal = cast<ConstantFP>(V)->getValue();
|
|
int64_t iVal = (int64_t) dVal;
|
|
return ConstantIntegral::get(DestTy, iVal);
|
|
}
|
|
case Instruction::IntToPtr: //always treated as unsigned
|
|
if (V->isNullValue()) // Is it a FP or Integral null value?
|
|
return ConstantPointerNull::get(cast<PointerType>(DestTy));
|
|
return 0; // Other pointer types cannot be casted
|
|
case Instruction::PtrToInt: // always treated as unsigned
|
|
if (V->isNullValue())
|
|
return ConstantIntegral::get(DestTy, 0);
|
|
return 0; // Other pointer types cannot be casted
|
|
case Instruction::UIToFP: {
|
|
// First, extract the unsigned integer value
|
|
uint64_t Val;
|
|
if (isa<ConstantInt>(V))
|
|
Val = cast<ConstantIntegral>(V)->getZExtValue();
|
|
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(V))
|
|
Val = CB->getValue() ? 1 : 0;
|
|
// Now generate the equivalent floating point value
|
|
double dVal = (double) Val;
|
|
return ConstantFP::get(DestTy, dVal);
|
|
}
|
|
case Instruction::SIToFP: {
|
|
// First, extract the signed integer value
|
|
int64_t Val;
|
|
if (isa<ConstantInt>(V))
|
|
Val = cast<ConstantIntegral>(V)->getSExtValue();
|
|
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(V))
|
|
Val = CB->getValue() ? -1 : 0;
|
|
// Now generate the equivalent floating point value
|
|
double dVal = (double) Val;
|
|
return ConstantFP::get(DestTy, dVal);
|
|
}
|
|
case Instruction::ZExt:
|
|
// Handle trunc directly here if it is a ConstantIntegral.
|
|
if (isa<ConstantInt>(V))
|
|
return ConstantInt::get(DestTy, cast<ConstantInt>(V)->getZExtValue());
|
|
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(V))
|
|
return ConstantInt::get(DestTy, CB->getValue() ? 1 : 0);
|
|
return 0;
|
|
case Instruction::SExt:
|
|
// A SExt always produces a signed value so we need to cast the value
|
|
// now before we try to cast it to the destiniation type.
|
|
if (isa<ConstantInt>(V))
|
|
return ConstantInt::get(DestTy, cast<ConstantInt>(V)->getSExtValue());
|
|
else if (const ConstantBool *CB = dyn_cast<ConstantBool>(V))
|
|
return ConstantInt::get(DestTy, CB->getValue() ? -1 : 0);
|
|
return 0;
|
|
case Instruction::Trunc:
|
|
// We just handle trunc directly here. The code below doesn't work for
|
|
// trunc to bool.
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V))
|
|
return ConstantIntegral::get(DestTy, CI->getZExtValue());
|
|
return 0;
|
|
case Instruction::BitCast:
|
|
if (SrcTy == DestTy)
|
|
return (Constant*)V; // no-op cast
|
|
|
|
// Check to see if we are casting a pointer to an aggregate to a pointer to
|
|
// the first element. If so, return the appropriate GEP instruction.
|
|
if (const PointerType *PTy = dyn_cast<PointerType>(V->getType()))
|
|
if (const PointerType *DPTy = dyn_cast<PointerType>(DestTy)) {
|
|
std::vector<Value*> IdxList;
|
|
IdxList.push_back(Constant::getNullValue(Type::IntTy));
|
|
const Type *ElTy = PTy->getElementType();
|
|
while (ElTy != DPTy->getElementType()) {
|
|
if (const StructType *STy = dyn_cast<StructType>(ElTy)) {
|
|
if (STy->getNumElements() == 0) break;
|
|
ElTy = STy->getElementType(0);
|
|
IdxList.push_back(Constant::getNullValue(Type::UIntTy));
|
|
} else if (const SequentialType *STy =
|
|
dyn_cast<SequentialType>(ElTy)) {
|
|
if (isa<PointerType>(ElTy)) break; // Can't index into pointers!
|
|
ElTy = STy->getElementType();
|
|
IdxList.push_back(IdxList[0]);
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (ElTy == DPTy->getElementType())
|
|
return ConstantExpr::getGetElementPtr(
|
|
const_cast<Constant*>(V),IdxList);
|
|
}
|
|
|
|
// Handle casts from one packed constant to another. We know that the src
|
|
// and dest type have the same size (otherwise its an illegal cast).
|
|
if (const PackedType *DestPTy = dyn_cast<PackedType>(DestTy)) {
|
|
if (const PackedType *SrcTy = dyn_cast<PackedType>(V->getType())) {
|
|
assert(DestPTy->getBitWidth() == SrcTy->getBitWidth() &&
|
|
"Not cast between same sized vectors!");
|
|
// First, check for null and undef
|
|
if (isa<ConstantAggregateZero>(V))
|
|
return Constant::getNullValue(DestTy);
|
|
if (isa<UndefValue>(V))
|
|
return UndefValue::get(DestTy);
|
|
|
|
if (const ConstantPacked *CP = dyn_cast<ConstantPacked>(V)) {
|
|
// This is a cast from a ConstantPacked of one type to a
|
|
// ConstantPacked of another type. Check to see if all elements of
|
|
// the input are simple.
|
|
bool AllSimpleConstants = true;
|
|
for (unsigned i = 0, e = CP->getNumOperands(); i != e; ++i) {
|
|
if (!isa<ConstantInt>(CP->getOperand(i)) &&
|
|
!isa<ConstantFP>(CP->getOperand(i))) {
|
|
AllSimpleConstants = false;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If all of the elements are simple constants, we can fold this.
|
|
if (AllSimpleConstants)
|
|
return CastConstantPacked(const_cast<ConstantPacked*>(CP), DestPTy);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Finally, implement bitcast folding now. The code below doesn't handle
|
|
// bitcast right.
|
|
if (isa<ConstantPointerNull>(V)) // ptr->ptr cast.
|
|
return ConstantPointerNull::get(cast<PointerType>(DestTy));
|
|
|
|
// Handle integral constant input.
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
|
|
// Integral -> Integral, must be changing sign.
|
|
if (DestTy->isIntegral())
|
|
return ConstantInt::get(DestTy, CI->getZExtValue());
|
|
|
|
if (DestTy->isFloatingPoint()) {
|
|
if (DestTy == Type::FloatTy)
|
|
return ConstantFP::get(DestTy, BitsToFloat(CI->getZExtValue()));
|
|
assert(DestTy == Type::DoubleTy && "Unknown FP type!");
|
|
return ConstantFP::get(DestTy, BitsToDouble(CI->getZExtValue()));
|
|
}
|
|
// Otherwise, can't fold this (packed?)
|
|
return 0;
|
|
}
|
|
|
|
// Handle ConstantFP input.
|
|
if (const ConstantFP *FP = dyn_cast<ConstantFP>(V)) {
|
|
// FP -> Integral.
|
|
if (DestTy->isIntegral()) {
|
|
if (DestTy == Type::IntTy || DestTy == Type::UIntTy)
|
|
return ConstantInt::get(DestTy, FloatToBits(FP->getValue()));
|
|
assert((DestTy == Type::LongTy || DestTy == Type::ULongTy)
|
|
&& "Incorrect integer type for bitcast!");
|
|
return ConstantInt::get(DestTy, DoubleToBits(FP->getValue()));
|
|
}
|
|
}
|
|
return 0;
|
|
default:
|
|
assert(!"Invalid CE CastInst opcode");
|
|
break;
|
|
}
|
|
|
|
assert(0 && "Failed to cast constant expression");
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldSelectInstruction(const Constant *Cond,
|
|
const Constant *V1,
|
|
const Constant *V2) {
|
|
if (const ConstantBool *CB = dyn_cast<ConstantBool>(Cond))
|
|
return const_cast<Constant*>(CB->getValue() ? V1 : V2);
|
|
|
|
if (isa<UndefValue>(V1)) return const_cast<Constant*>(V2);
|
|
if (isa<UndefValue>(V2)) return const_cast<Constant*>(V1);
|
|
if (isa<UndefValue>(Cond)) return const_cast<Constant*>(V1);
|
|
if (V1 == V2) return const_cast<Constant*>(V1);
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldExtractElementInstruction(const Constant *Val,
|
|
const Constant *Idx) {
|
|
if (isa<UndefValue>(Val)) // ee(undef, x) -> undef
|
|
return UndefValue::get(cast<PackedType>(Val->getType())->getElementType());
|
|
if (Val->isNullValue()) // ee(zero, x) -> zero
|
|
return Constant::getNullValue(
|
|
cast<PackedType>(Val->getType())->getElementType());
|
|
|
|
if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) {
|
|
if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx)) {
|
|
return const_cast<Constant*>(CVal->getOperand(CIdx->getZExtValue()));
|
|
} else if (isa<UndefValue>(Idx)) {
|
|
// ee({w,x,y,z}, undef) -> w (an arbitrary value).
|
|
return const_cast<Constant*>(CVal->getOperand(0));
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldInsertElementInstruction(const Constant *Val,
|
|
const Constant *Elt,
|
|
const Constant *Idx) {
|
|
const ConstantInt *CIdx = dyn_cast<ConstantInt>(Idx);
|
|
if (!CIdx) return 0;
|
|
uint64_t idxVal = CIdx->getZExtValue();
|
|
if (isa<UndefValue>(Val)) {
|
|
// Insertion of scalar constant into packed undef
|
|
// Optimize away insertion of undef
|
|
if (isa<UndefValue>(Elt))
|
|
return const_cast<Constant*>(Val);
|
|
// Otherwise break the aggregate undef into multiple undefs and do
|
|
// the insertion
|
|
unsigned numOps =
|
|
cast<PackedType>(Val->getType())->getNumElements();
|
|
std::vector<Constant*> Ops;
|
|
Ops.reserve(numOps);
|
|
for (unsigned i = 0; i < numOps; ++i) {
|
|
const Constant *Op =
|
|
(i == idxVal) ? Elt : UndefValue::get(Elt->getType());
|
|
Ops.push_back(const_cast<Constant*>(Op));
|
|
}
|
|
return ConstantPacked::get(Ops);
|
|
}
|
|
if (isa<ConstantAggregateZero>(Val)) {
|
|
// Insertion of scalar constant into packed aggregate zero
|
|
// Optimize away insertion of zero
|
|
if (Elt->isNullValue())
|
|
return const_cast<Constant*>(Val);
|
|
// Otherwise break the aggregate zero into multiple zeros and do
|
|
// the insertion
|
|
unsigned numOps =
|
|
cast<PackedType>(Val->getType())->getNumElements();
|
|
std::vector<Constant*> Ops;
|
|
Ops.reserve(numOps);
|
|
for (unsigned i = 0; i < numOps; ++i) {
|
|
const Constant *Op =
|
|
(i == idxVal) ? Elt : Constant::getNullValue(Elt->getType());
|
|
Ops.push_back(const_cast<Constant*>(Op));
|
|
}
|
|
return ConstantPacked::get(Ops);
|
|
}
|
|
if (const ConstantPacked *CVal = dyn_cast<ConstantPacked>(Val)) {
|
|
// Insertion of scalar constant into packed constant
|
|
std::vector<Constant*> Ops;
|
|
Ops.reserve(CVal->getNumOperands());
|
|
for (unsigned i = 0; i < CVal->getNumOperands(); ++i) {
|
|
const Constant *Op =
|
|
(i == idxVal) ? Elt : cast<Constant>(CVal->getOperand(i));
|
|
Ops.push_back(const_cast<Constant*>(Op));
|
|
}
|
|
return ConstantPacked::get(Ops);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldShuffleVectorInstruction(const Constant *V1,
|
|
const Constant *V2,
|
|
const Constant *Mask) {
|
|
// TODO:
|
|
return 0;
|
|
}
|
|
|
|
|
|
/// isZeroSizedType - This type is zero sized if its an array or structure of
|
|
/// zero sized types. The only leaf zero sized type is an empty structure.
|
|
static bool isMaybeZeroSizedType(const Type *Ty) {
|
|
if (isa<OpaqueType>(Ty)) return true; // Can't say.
|
|
if (const StructType *STy = dyn_cast<StructType>(Ty)) {
|
|
|
|
// If all of elements have zero size, this does too.
|
|
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i)
|
|
if (!isMaybeZeroSizedType(STy->getElementType(i))) return false;
|
|
return true;
|
|
|
|
} else if (const ArrayType *ATy = dyn_cast<ArrayType>(Ty)) {
|
|
return isMaybeZeroSizedType(ATy->getElementType());
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// IdxCompare - Compare the two constants as though they were getelementptr
|
|
/// indices. This allows coersion of the types to be the same thing.
|
|
///
|
|
/// If the two constants are the "same" (after coersion), return 0. If the
|
|
/// first is less than the second, return -1, if the second is less than the
|
|
/// first, return 1. If the constants are not integral, return -2.
|
|
///
|
|
static int IdxCompare(Constant *C1, Constant *C2, const Type *ElTy) {
|
|
if (C1 == C2) return 0;
|
|
|
|
// Ok, we found a different index. Are either of the operands ConstantExprs?
|
|
// If so, we can't do anything with them.
|
|
if (!isa<ConstantInt>(C1) || !isa<ConstantInt>(C2))
|
|
return -2; // don't know!
|
|
|
|
// Ok, we have two differing integer indices. Sign extend them to be the same
|
|
// type. Long is always big enough, so we use it.
|
|
if (C1->getType() != Type::LongTy && C1->getType() != Type::ULongTy)
|
|
C1 = ConstantExpr::getSExt(C1, Type::LongTy);
|
|
else
|
|
C1 = ConstantExpr::getBitCast(C1, Type::LongTy);
|
|
if (C2->getType() != Type::LongTy && C1->getType() != Type::ULongTy)
|
|
C2 = ConstantExpr::getSExt(C2, Type::LongTy);
|
|
else
|
|
C2 = ConstantExpr::getBitCast(C2, Type::LongTy);
|
|
|
|
if (C1 == C2) return 0; // Are they just differing types?
|
|
|
|
// If the type being indexed over is really just a zero sized type, there is
|
|
// no pointer difference being made here.
|
|
if (isMaybeZeroSizedType(ElTy))
|
|
return -2; // dunno.
|
|
|
|
// If they are really different, now that they are the same type, then we
|
|
// found a difference!
|
|
if (cast<ConstantInt>(C1)->getSExtValue() <
|
|
cast<ConstantInt>(C2)->getSExtValue())
|
|
return -1;
|
|
else
|
|
return 1;
|
|
}
|
|
|
|
/// evaluateRelation - This function determines if there is anything we can
|
|
/// decide about the two constants provided. This doesn't need to handle simple
|
|
/// things like integer comparisons, but should instead handle ConstantExprs
|
|
/// and GlobalValues. If we can determine that the two constants have a
|
|
/// particular relation to each other, we should return the corresponding SetCC
|
|
/// code, otherwise return Instruction::BinaryOpsEnd.
|
|
///
|
|
/// To simplify this code we canonicalize the relation so that the first
|
|
/// operand is always the most "complex" of the two. We consider simple
|
|
/// constants (like ConstantInt) to be the simplest, followed by
|
|
/// GlobalValues, followed by ConstantExpr's (the most complex).
|
|
///
|
|
static Instruction::BinaryOps evaluateRelation(Constant *V1, Constant *V2) {
|
|
assert(V1->getType() == V2->getType() &&
|
|
"Cannot compare different types of values!");
|
|
if (V1 == V2) return Instruction::SetEQ;
|
|
|
|
if (!isa<ConstantExpr>(V1) && !isa<GlobalValue>(V1)) {
|
|
if (!isa<GlobalValue>(V2) && !isa<ConstantExpr>(V2)) {
|
|
// We distilled this down to a simple case, use the standard constant
|
|
// folder.
|
|
ConstantBool *R = dyn_cast<ConstantBool>(ConstantExpr::getSetEQ(V1, V2));
|
|
if (R && R->getValue()) return Instruction::SetEQ;
|
|
R = dyn_cast<ConstantBool>(ConstantExpr::getSetLT(V1, V2));
|
|
if (R && R->getValue()) return Instruction::SetLT;
|
|
R = dyn_cast<ConstantBool>(ConstantExpr::getSetGT(V1, V2));
|
|
if (R && R->getValue()) return Instruction::SetGT;
|
|
|
|
// If we couldn't figure it out, bail.
|
|
return Instruction::BinaryOpsEnd;
|
|
}
|
|
|
|
// If the first operand is simple, swap operands.
|
|
Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1);
|
|
if (SwappedRelation != Instruction::BinaryOpsEnd)
|
|
return SetCondInst::getSwappedCondition(SwappedRelation);
|
|
|
|
} else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(V1)) {
|
|
if (isa<ConstantExpr>(V2)) { // Swap as necessary.
|
|
Instruction::BinaryOps SwappedRelation = evaluateRelation(V2, V1);
|
|
if (SwappedRelation != Instruction::BinaryOpsEnd)
|
|
return SetCondInst::getSwappedCondition(SwappedRelation);
|
|
else
|
|
return Instruction::BinaryOpsEnd;
|
|
}
|
|
|
|
// Now we know that the RHS is a GlobalValue or simple constant,
|
|
// which (since the types must match) means that it's a ConstantPointerNull.
|
|
if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
|
|
if (!CPR1->hasExternalWeakLinkage() || !CPR2->hasExternalWeakLinkage())
|
|
return Instruction::SetNE;
|
|
} else {
|
|
// GlobalVals can never be null.
|
|
assert(isa<ConstantPointerNull>(V2) && "Canonicalization guarantee!");
|
|
if (!CPR1->hasExternalWeakLinkage())
|
|
return Instruction::SetNE;
|
|
}
|
|
} else {
|
|
// Ok, the LHS is known to be a constantexpr. The RHS can be any of a
|
|
// constantexpr, a CPR, or a simple constant.
|
|
ConstantExpr *CE1 = cast<ConstantExpr>(V1);
|
|
Constant *CE1Op0 = CE1->getOperand(0);
|
|
|
|
switch (CE1->getOpcode()) {
|
|
case Instruction::Trunc:
|
|
case Instruction::FPTrunc:
|
|
case Instruction::FPExt:
|
|
case Instruction::FPToUI:
|
|
case Instruction::FPToSI:
|
|
break; // We don't do anything with floating point.
|
|
case Instruction::ZExt:
|
|
case Instruction::SExt:
|
|
case Instruction::UIToFP:
|
|
case Instruction::SIToFP:
|
|
case Instruction::PtrToInt:
|
|
case Instruction::IntToPtr:
|
|
case Instruction::BitCast:
|
|
// If the cast is not actually changing bits, and the second operand is a
|
|
// null pointer, do the comparison with the pre-casted value.
|
|
if (V2->isNullValue() &&
|
|
(isa<PointerType>(CE1->getType()) || CE1->getType()->isIntegral()))
|
|
return evaluateRelation(CE1Op0,
|
|
Constant::getNullValue(CE1Op0->getType()));
|
|
|
|
// If the dest type is a pointer type, and the RHS is a constantexpr cast
|
|
// from the same type as the src of the LHS, evaluate the inputs. This is
|
|
// important for things like "seteq (cast 4 to int*), (cast 5 to int*)",
|
|
// which happens a lot in compilers with tagged integers.
|
|
if (ConstantExpr *CE2 = dyn_cast<ConstantExpr>(V2))
|
|
if (isa<PointerType>(CE1->getType()) && CE2->isCast() &&
|
|
CE1->getOperand(0)->getType() == CE2->getOperand(0)->getType() &&
|
|
CE1->getOperand(0)->getType()->isIntegral()) {
|
|
return evaluateRelation(CE1->getOperand(0), CE2->getOperand(0));
|
|
}
|
|
break;
|
|
|
|
case Instruction::GetElementPtr:
|
|
// Ok, since this is a getelementptr, we know that the constant has a
|
|
// pointer type. Check the various cases.
|
|
if (isa<ConstantPointerNull>(V2)) {
|
|
// If we are comparing a GEP to a null pointer, check to see if the base
|
|
// of the GEP equals the null pointer.
|
|
if (GlobalValue *GV = dyn_cast<GlobalValue>(CE1Op0)) {
|
|
if (GV->hasExternalWeakLinkage())
|
|
// Weak linkage GVals could be zero or not. We're comparing that
|
|
// to null pointer so its greater-or-equal
|
|
return Instruction::SetGE;
|
|
else
|
|
// If its not weak linkage, the GVal must have a non-zero address
|
|
// so the result is greater-than
|
|
return Instruction::SetGT;
|
|
} else if (isa<ConstantPointerNull>(CE1Op0)) {
|
|
// If we are indexing from a null pointer, check to see if we have any
|
|
// non-zero indices.
|
|
for (unsigned i = 1, e = CE1->getNumOperands(); i != e; ++i)
|
|
if (!CE1->getOperand(i)->isNullValue())
|
|
// Offsetting from null, must not be equal.
|
|
return Instruction::SetGT;
|
|
// Only zero indexes from null, must still be zero.
|
|
return Instruction::SetEQ;
|
|
}
|
|
// Otherwise, we can't really say if the first operand is null or not.
|
|
} else if (const GlobalValue *CPR2 = dyn_cast<GlobalValue>(V2)) {
|
|
if (isa<ConstantPointerNull>(CE1Op0)) {
|
|
if (CPR2->hasExternalWeakLinkage())
|
|
// Weak linkage GVals could be zero or not. We're comparing it to
|
|
// a null pointer, so its less-or-equal
|
|
return Instruction::SetLE;
|
|
else
|
|
// If its not weak linkage, the GVal must have a non-zero address
|
|
// so the result is less-than
|
|
return Instruction::SetLT;
|
|
} else if (const GlobalValue *CPR1 = dyn_cast<GlobalValue>(CE1Op0)) {
|
|
if (CPR1 == CPR2) {
|
|
// If this is a getelementptr of the same global, then it must be
|
|
// different. Because the types must match, the getelementptr could
|
|
// only have at most one index, and because we fold getelementptr's
|
|
// with a single zero index, it must be nonzero.
|
|
assert(CE1->getNumOperands() == 2 &&
|
|
!CE1->getOperand(1)->isNullValue() &&
|
|
"Suprising getelementptr!");
|
|
return Instruction::SetGT;
|
|
} else {
|
|
// If they are different globals, we don't know what the value is,
|
|
// but they can't be equal.
|
|
return Instruction::SetNE;
|
|
}
|
|
}
|
|
} else {
|
|
const ConstantExpr *CE2 = cast<ConstantExpr>(V2);
|
|
const Constant *CE2Op0 = CE2->getOperand(0);
|
|
|
|
// There are MANY other foldings that we could perform here. They will
|
|
// probably be added on demand, as they seem needed.
|
|
switch (CE2->getOpcode()) {
|
|
default: break;
|
|
case Instruction::GetElementPtr:
|
|
// By far the most common case to handle is when the base pointers are
|
|
// obviously to the same or different globals.
|
|
if (isa<GlobalValue>(CE1Op0) && isa<GlobalValue>(CE2Op0)) {
|
|
if (CE1Op0 != CE2Op0) // Don't know relative ordering, but not equal
|
|
return Instruction::SetNE;
|
|
// Ok, we know that both getelementptr instructions are based on the
|
|
// same global. From this, we can precisely determine the relative
|
|
// ordering of the resultant pointers.
|
|
unsigned i = 1;
|
|
|
|
// Compare all of the operands the GEP's have in common.
|
|
gep_type_iterator GTI = gep_type_begin(CE1);
|
|
for (;i != CE1->getNumOperands() && i != CE2->getNumOperands();
|
|
++i, ++GTI)
|
|
switch (IdxCompare(CE1->getOperand(i), CE2->getOperand(i),
|
|
GTI.getIndexedType())) {
|
|
case -1: return Instruction::SetLT;
|
|
case 1: return Instruction::SetGT;
|
|
case -2: return Instruction::BinaryOpsEnd;
|
|
}
|
|
|
|
// Ok, we ran out of things they have in common. If any leftovers
|
|
// are non-zero then we have a difference, otherwise we are equal.
|
|
for (; i < CE1->getNumOperands(); ++i)
|
|
if (!CE1->getOperand(i)->isNullValue())
|
|
if (isa<ConstantIntegral>(CE1->getOperand(i)))
|
|
return Instruction::SetGT;
|
|
else
|
|
return Instruction::BinaryOpsEnd; // Might be equal.
|
|
|
|
for (; i < CE2->getNumOperands(); ++i)
|
|
if (!CE2->getOperand(i)->isNullValue())
|
|
if (isa<ConstantIntegral>(CE2->getOperand(i)))
|
|
return Instruction::SetLT;
|
|
else
|
|
return Instruction::BinaryOpsEnd; // Might be equal.
|
|
return Instruction::SetEQ;
|
|
}
|
|
}
|
|
}
|
|
|
|
default:
|
|
break;
|
|
}
|
|
}
|
|
|
|
return Instruction::BinaryOpsEnd;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
|
|
const Constant *V1,
|
|
const Constant *V2) {
|
|
Constant *C = 0;
|
|
switch (Opcode) {
|
|
default: break;
|
|
case Instruction::Add: C = ConstRules::get(V1, V2).add(V1, V2); break;
|
|
case Instruction::Sub: C = ConstRules::get(V1, V2).sub(V1, V2); break;
|
|
case Instruction::Mul: C = ConstRules::get(V1, V2).mul(V1, V2); break;
|
|
case Instruction::UDiv: C = ConstRules::get(V1, V2).udiv(V1, V2); break;
|
|
case Instruction::SDiv: C = ConstRules::get(V1, V2).sdiv(V1, V2); break;
|
|
case Instruction::FDiv: C = ConstRules::get(V1, V2).fdiv(V1, V2); break;
|
|
case Instruction::URem: C = ConstRules::get(V1, V2).urem(V1, V2); break;
|
|
case Instruction::SRem: C = ConstRules::get(V1, V2).srem(V1, V2); break;
|
|
case Instruction::FRem: C = ConstRules::get(V1, V2).frem(V1, V2); break;
|
|
case Instruction::And: C = ConstRules::get(V1, V2).op_and(V1, V2); break;
|
|
case Instruction::Or: C = ConstRules::get(V1, V2).op_or (V1, V2); break;
|
|
case Instruction::Xor: C = ConstRules::get(V1, V2).op_xor(V1, V2); break;
|
|
case Instruction::Shl: C = ConstRules::get(V1, V2).shl(V1, V2); break;
|
|
case Instruction::LShr: C = ConstRules::get(V1, V2).lshr(V1, V2); break;
|
|
case Instruction::AShr: C = ConstRules::get(V1, V2).ashr(V1, V2); break;
|
|
case Instruction::SetEQ:
|
|
// SetEQ(null,GV) -> false
|
|
if (V1->isNullValue()) {
|
|
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
|
|
if (!GV->hasExternalWeakLinkage())
|
|
return ConstantBool::getFalse();
|
|
// SetEQ(GV,null) -> false
|
|
} else if (V2->isNullValue()) {
|
|
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
|
|
if (!GV->hasExternalWeakLinkage())
|
|
return ConstantBool::getFalse();
|
|
}
|
|
C = ConstRules::get(V1, V2).equalto(V1, V2);
|
|
break;
|
|
case Instruction::SetLT: C = ConstRules::get(V1, V2).lessthan(V1, V2);break;
|
|
case Instruction::SetGT: C = ConstRules::get(V1, V2).lessthan(V2, V1);break;
|
|
case Instruction::SetNE:
|
|
// SetNE(null,GV) -> true
|
|
if (V1->isNullValue()) {
|
|
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V2))
|
|
if (!GV->hasExternalWeakLinkage())
|
|
return ConstantBool::getTrue();
|
|
// SetNE(GV,null) -> true
|
|
} else if (V2->isNullValue()) {
|
|
if (const GlobalValue *GV = dyn_cast<GlobalValue>(V1))
|
|
if (!GV->hasExternalWeakLinkage())
|
|
return ConstantBool::getTrue();
|
|
}
|
|
// V1 != V2 === !(V1 == V2)
|
|
C = ConstRules::get(V1, V2).equalto(V1, V2);
|
|
if (C) return ConstantExpr::getNot(C);
|
|
break;
|
|
case Instruction::SetLE: // V1 <= V2 === !(V2 < V1)
|
|
C = ConstRules::get(V1, V2).lessthan(V2, V1);
|
|
if (C) return ConstantExpr::getNot(C);
|
|
break;
|
|
case Instruction::SetGE: // V1 >= V2 === !(V1 < V2)
|
|
C = ConstRules::get(V1, V2).lessthan(V1, V2);
|
|
if (C) return ConstantExpr::getNot(C);
|
|
break;
|
|
}
|
|
|
|
// If we successfully folded the expression, return it now.
|
|
if (C) return C;
|
|
|
|
if (SetCondInst::isComparison(Opcode)) {
|
|
if (isa<UndefValue>(V1) || isa<UndefValue>(V2))
|
|
return UndefValue::get(Type::BoolTy);
|
|
switch (evaluateRelation(const_cast<Constant*>(V1),
|
|
const_cast<Constant*>(V2))) {
|
|
default: assert(0 && "Unknown relational!");
|
|
case Instruction::BinaryOpsEnd:
|
|
break; // Couldn't determine anything about these constants.
|
|
case Instruction::SetEQ: // We know the constants are equal!
|
|
// If we know the constants are equal, we can decide the result of this
|
|
// computation precisely.
|
|
return ConstantBool::get(Opcode == Instruction::SetEQ ||
|
|
Opcode == Instruction::SetLE ||
|
|
Opcode == Instruction::SetGE);
|
|
case Instruction::SetLT:
|
|
// If we know that V1 < V2, we can decide the result of this computation
|
|
// precisely.
|
|
return ConstantBool::get(Opcode == Instruction::SetLT ||
|
|
Opcode == Instruction::SetNE ||
|
|
Opcode == Instruction::SetLE);
|
|
case Instruction::SetGT:
|
|
// If we know that V1 > V2, we can decide the result of this computation
|
|
// precisely.
|
|
return ConstantBool::get(Opcode == Instruction::SetGT ||
|
|
Opcode == Instruction::SetNE ||
|
|
Opcode == Instruction::SetGE);
|
|
case Instruction::SetLE:
|
|
// If we know that V1 <= V2, we can only partially decide this relation.
|
|
if (Opcode == Instruction::SetGT) return ConstantBool::getFalse();
|
|
if (Opcode == Instruction::SetLT) return ConstantBool::getTrue();
|
|
break;
|
|
|
|
case Instruction::SetGE:
|
|
// If we know that V1 >= V2, we can only partially decide this relation.
|
|
if (Opcode == Instruction::SetLT) return ConstantBool::getFalse();
|
|
if (Opcode == Instruction::SetGT) return ConstantBool::getTrue();
|
|
break;
|
|
|
|
case Instruction::SetNE:
|
|
// If we know that V1 != V2, we can only partially decide this relation.
|
|
if (Opcode == Instruction::SetEQ) return ConstantBool::getFalse();
|
|
if (Opcode == Instruction::SetNE) return ConstantBool::getTrue();
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (isa<UndefValue>(V1) || isa<UndefValue>(V2)) {
|
|
switch (Opcode) {
|
|
case Instruction::Add:
|
|
case Instruction::Sub:
|
|
case Instruction::Xor:
|
|
return UndefValue::get(V1->getType());
|
|
|
|
case Instruction::Mul:
|
|
case Instruction::And:
|
|
return Constant::getNullValue(V1->getType());
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
case Instruction::FDiv:
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::FRem:
|
|
if (!isa<UndefValue>(V2)) // undef / X -> 0
|
|
return Constant::getNullValue(V1->getType());
|
|
return const_cast<Constant*>(V2); // X / undef -> undef
|
|
case Instruction::Or: // X | undef -> -1
|
|
return ConstantInt::getAllOnesValue(V1->getType());
|
|
case Instruction::LShr:
|
|
if (isa<UndefValue>(V2) && isa<UndefValue>(V1))
|
|
return const_cast<Constant*>(V1); // undef lshr undef -> undef
|
|
return Constant::getNullValue(V1->getType()); // X lshr undef -> 0
|
|
// undef lshr X -> 0
|
|
case Instruction::AShr:
|
|
if (!isa<UndefValue>(V2))
|
|
return const_cast<Constant*>(V1); // undef ashr X --> undef
|
|
else if (isa<UndefValue>(V1))
|
|
return const_cast<Constant*>(V1); // undef ashr undef -> undef
|
|
else
|
|
return const_cast<Constant*>(V1); // X ashr undef --> X
|
|
case Instruction::Shl:
|
|
// undef << X -> 0 or X << undef -> 0
|
|
return Constant::getNullValue(V1->getType());
|
|
}
|
|
}
|
|
|
|
if (const ConstantExpr *CE1 = dyn_cast<ConstantExpr>(V1)) {
|
|
if (isa<ConstantExpr>(V2)) {
|
|
// There are many possible foldings we could do here. We should probably
|
|
// at least fold add of a pointer with an integer into the appropriate
|
|
// getelementptr. This will improve alias analysis a bit.
|
|
} else {
|
|
// Just implement a couple of simple identities.
|
|
switch (Opcode) {
|
|
case Instruction::Add:
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V1); // X + 0 == X
|
|
break;
|
|
case Instruction::Sub:
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V1); // X - 0 == X
|
|
break;
|
|
case Instruction::Mul:
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V2); // X * 0 == 0
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
|
|
if (CI->getZExtValue() == 1)
|
|
return const_cast<Constant*>(V1); // X * 1 == X
|
|
break;
|
|
case Instruction::UDiv:
|
|
case Instruction::SDiv:
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
|
|
if (CI->getZExtValue() == 1)
|
|
return const_cast<Constant*>(V1); // X / 1 == X
|
|
break;
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
|
|
if (CI->getZExtValue() == 1)
|
|
return Constant::getNullValue(CI->getType()); // X % 1 == 0
|
|
break;
|
|
case Instruction::And:
|
|
if (cast<ConstantIntegral>(V2)->isAllOnesValue())
|
|
return const_cast<Constant*>(V1); // X & -1 == X
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V2); // X & 0 == 0
|
|
if (CE1->isCast() && isa<GlobalValue>(CE1->getOperand(0))) {
|
|
GlobalValue *CPR = cast<GlobalValue>(CE1->getOperand(0));
|
|
|
|
// Functions are at least 4-byte aligned. If and'ing the address of a
|
|
// function with a constant < 4, fold it to zero.
|
|
if (const ConstantInt *CI = dyn_cast<ConstantInt>(V2))
|
|
if (CI->getZExtValue() < 4 && isa<Function>(CPR))
|
|
return Constant::getNullValue(CI->getType());
|
|
}
|
|
break;
|
|
case Instruction::Or:
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V1); // X | 0 == X
|
|
if (cast<ConstantIntegral>(V2)->isAllOnesValue())
|
|
return const_cast<Constant*>(V2); // X | -1 == -1
|
|
break;
|
|
case Instruction::Xor:
|
|
if (V2->isNullValue()) return const_cast<Constant*>(V1); // X ^ 0 == X
|
|
break;
|
|
}
|
|
}
|
|
|
|
} else if (isa<ConstantExpr>(V2)) {
|
|
// If V2 is a constant expr and V1 isn't, flop them around and fold the
|
|
// other way if possible.
|
|
switch (Opcode) {
|
|
case Instruction::Add:
|
|
case Instruction::Mul:
|
|
case Instruction::And:
|
|
case Instruction::Or:
|
|
case Instruction::Xor:
|
|
case Instruction::SetEQ:
|
|
case Instruction::SetNE:
|
|
// No change of opcode required.
|
|
return ConstantFoldBinaryInstruction(Opcode, V2, V1);
|
|
|
|
case Instruction::SetLT:
|
|
case Instruction::SetGT:
|
|
case Instruction::SetLE:
|
|
case Instruction::SetGE:
|
|
// Change the opcode as necessary to swap the operands.
|
|
Opcode = SetCondInst::getSwappedCondition((Instruction::BinaryOps)Opcode);
|
|
return ConstantFoldBinaryInstruction(Opcode, V2, V1);
|
|
|
|
case Instruction::Shl:
|
|
case Instruction::LShr:
|
|
case Instruction::AShr:
|
|
case Instruction::Sub:
|
|
case Instruction::SDiv:
|
|
case Instruction::UDiv:
|
|
case Instruction::FDiv:
|
|
case Instruction::URem:
|
|
case Instruction::SRem:
|
|
case Instruction::FRem:
|
|
default: // These instructions cannot be flopped around.
|
|
break;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldCompare(
|
|
unsigned opcode, Constant *C1, Constant *C2, unsigned short predicate)
|
|
{
|
|
// Place holder for future folding of ICmp and FCmp instructions
|
|
return 0;
|
|
}
|
|
|
|
Constant *llvm::ConstantFoldGetElementPtr(const Constant *C,
|
|
const std::vector<Value*> &IdxList) {
|
|
if (IdxList.size() == 0 ||
|
|
(IdxList.size() == 1 && cast<Constant>(IdxList[0])->isNullValue()))
|
|
return const_cast<Constant*>(C);
|
|
|
|
if (isa<UndefValue>(C)) {
|
|
const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList,
|
|
true);
|
|
assert(Ty != 0 && "Invalid indices for GEP!");
|
|
return UndefValue::get(PointerType::get(Ty));
|
|
}
|
|
|
|
Constant *Idx0 = cast<Constant>(IdxList[0]);
|
|
if (C->isNullValue()) {
|
|
bool isNull = true;
|
|
for (unsigned i = 0, e = IdxList.size(); i != e; ++i)
|
|
if (!cast<Constant>(IdxList[i])->isNullValue()) {
|
|
isNull = false;
|
|
break;
|
|
}
|
|
if (isNull) {
|
|
const Type *Ty = GetElementPtrInst::getIndexedType(C->getType(), IdxList,
|
|
true);
|
|
assert(Ty != 0 && "Invalid indices for GEP!");
|
|
return ConstantPointerNull::get(PointerType::get(Ty));
|
|
}
|
|
|
|
if (IdxList.size() == 1) {
|
|
const Type *ElTy = cast<PointerType>(C->getType())->getElementType();
|
|
if (uint32_t ElSize = ElTy->getPrimitiveSize()) {
|
|
// gep null, C is equal to C*sizeof(nullty). If nullty is a known llvm
|
|
// type, we can statically fold this.
|
|
Constant *R = ConstantInt::get(Type::UIntTy, ElSize);
|
|
// We know R is unsigned, Idx0 is signed because it must be an index
|
|
// through a sequential type (gep pointer operand) which is always
|
|
// signed.
|
|
R = ConstantExpr::getSExtOrBitCast(R, Idx0->getType());
|
|
R = ConstantExpr::getMul(R, Idx0); // signed multiply
|
|
// R is a signed integer, C is the GEP pointer so -> IntToPtr
|
|
return ConstantExpr::getIntToPtr(R, C->getType());
|
|
}
|
|
}
|
|
}
|
|
|
|
if (ConstantExpr *CE = dyn_cast<ConstantExpr>(const_cast<Constant*>(C))) {
|
|
// Combine Indices - If the source pointer to this getelementptr instruction
|
|
// is a getelementptr instruction, combine the indices of the two
|
|
// getelementptr instructions into a single instruction.
|
|
//
|
|
if (CE->getOpcode() == Instruction::GetElementPtr) {
|
|
const Type *LastTy = 0;
|
|
for (gep_type_iterator I = gep_type_begin(CE), E = gep_type_end(CE);
|
|
I != E; ++I)
|
|
LastTy = *I;
|
|
|
|
if ((LastTy && isa<ArrayType>(LastTy)) || Idx0->isNullValue()) {
|
|
std::vector<Value*> NewIndices;
|
|
NewIndices.reserve(IdxList.size() + CE->getNumOperands());
|
|
for (unsigned i = 1, e = CE->getNumOperands()-1; i != e; ++i)
|
|
NewIndices.push_back(CE->getOperand(i));
|
|
|
|
// Add the last index of the source with the first index of the new GEP.
|
|
// Make sure to handle the case when they are actually different types.
|
|
Constant *Combined = CE->getOperand(CE->getNumOperands()-1);
|
|
// Otherwise it must be an array.
|
|
if (!Idx0->isNullValue()) {
|
|
const Type *IdxTy = Combined->getType();
|
|
if (IdxTy != Idx0->getType()) {
|
|
Constant *C1 = ConstantExpr::getSExtOrBitCast(Idx0, Type::LongTy);
|
|
Constant *C2 = ConstantExpr::getSExtOrBitCast(Combined,
|
|
Type::LongTy);
|
|
Combined = ConstantExpr::get(Instruction::Add, C1, C2);
|
|
} else {
|
|
Combined =
|
|
ConstantExpr::get(Instruction::Add, Idx0, Combined);
|
|
}
|
|
}
|
|
|
|
NewIndices.push_back(Combined);
|
|
NewIndices.insert(NewIndices.end(), IdxList.begin()+1, IdxList.end());
|
|
return ConstantExpr::getGetElementPtr(CE->getOperand(0), NewIndices);
|
|
}
|
|
}
|
|
|
|
// Implement folding of:
|
|
// int* getelementptr ([2 x int]* cast ([3 x int]* %X to [2 x int]*),
|
|
// long 0, long 0)
|
|
// To: int* getelementptr ([3 x int]* %X, long 0, long 0)
|
|
//
|
|
if (CE->isCast() && IdxList.size() > 1 && Idx0->isNullValue())
|
|
if (const PointerType *SPT =
|
|
dyn_cast<PointerType>(CE->getOperand(0)->getType()))
|
|
if (const ArrayType *SAT = dyn_cast<ArrayType>(SPT->getElementType()))
|
|
if (const ArrayType *CAT =
|
|
dyn_cast<ArrayType>(cast<PointerType>(C->getType())->getElementType()))
|
|
if (CAT->getElementType() == SAT->getElementType())
|
|
return ConstantExpr::getGetElementPtr(
|
|
(Constant*)CE->getOperand(0), IdxList);
|
|
}
|
|
return 0;
|
|
}
|
|
|