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Revert overly aggressive interpretation of noalias

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40635 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Christopher Lamb 2007-07-31 16:18:07 +00:00
parent 1013b4d749
commit 321ff4e6d5
2 changed files with 1 additions and 44 deletions
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33
lib/Analysis/BasicAliasAnalysis.cpp
View File

@ -18,7 +18,6 @@
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/ParameterAttributes.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/Pass.h"
@ -295,21 +294,6 @@ BasicAliasAnalysis::alias(const Value *V1, unsigned V1Size,
// Pointing at a discernible object?
if (O1) {
// Check for noalias attribute
if (isa<Argument>(O1)) {
const Argument *Arg = cast<Argument>(O1);
const Function *Func = Arg->getParent();
const ParamAttrsList *Attr = Func->getFunctionType()->getParamAttrs();
if (Attr) {
unsigned Idx = 1;
for (Function::const_arg_iterator I = Func->arg_begin(),
E = Func->arg_end(); I != E; ++I, ++Idx) {
if (&(*I) == Arg &&
Attr->paramHasAttr(Idx, ParamAttr::NoAlias))
return NoAlias;
}
}
}
if (O2) {
if (isa<Argument>(O1)) {
// Incoming argument cannot alias locally allocated object!
@ -323,22 +307,7 @@ BasicAliasAnalysis::alias(const Value *V1, unsigned V1Size,
// If they are two different objects, we know that we have no alias...
return NoAlias;
}
// Check for noalias atrribute independently from above logic
if (isa<Argument>(O2)) {
const Argument *Arg = cast<Argument>(O2);
const Function *Func = Arg->getParent();
const ParamAttrsList *Attr = Func->getFunctionType()->getParamAttrs();
if (Attr) {
unsigned Idx = 1;
for (Function::const_arg_iterator I = Func->arg_begin(),
E = Func->arg_end(); I != E; ++I, ++Idx) {
if (&(*I) == Arg &&
Attr->paramHasAttr(Idx, ParamAttr::NoAlias))
return NoAlias;
}
}
}
// If they are the same object, they we can look at the indexes. If they
// index off of the object is the same for both pointers, they must alias.
// If they are provably different, they must not alias. Otherwise, we

12
test/Analysis/BasicAA/2007-07-31-NoAliasTest.ll
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@ -1,12 +0,0 @@
; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep '1 may alias'
; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep '5 no alias'
; RUN: llvm-as %s -o - | opt -aa-eval -print-may-aliases -disable-output |& grep 'MayAlias: i32* %ptr4, i32* %ptr2'
define void @_Z3fooPiS_RiS_(i32* noalias %ptr1, i32* %ptr2, i32* noalias %ptr3, i32* %ptr4) {
entry:
store i32 0, i32* %ptr1
store i32 0, i32* %ptr2
store i32 0, i32* %ptr3
store i32 0, i32* %ptr4
ret void
}