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canonicalize inttoptr and ptrtoint instructions which cast pointers

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to/from integer types that are not intptr_t to convert to intptr_t
then do an integer conversion to the dest type.  This exposes the
cast to the optimizer.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@67638 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-03-24 18:35:40 +00:00
parent 1f8c564d7d
commit a0e6969bbe
2 changed files with 53 additions and 5 deletions
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42
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -218,7 +218,7 @@ namespace {
Instruction *visitFPToSI(FPToSIInst &FI);
Instruction *visitUIToFP(CastInst &CI);
Instruction *visitSIToFP(CastInst &CI);
Instruction *visitPtrToInt(CastInst &CI);
Instruction *visitPtrToInt(PtrToIntInst &CI);
Instruction *visitIntToPtr(IntToPtrInst &CI);
Instruction *visitBitCast(BitCastInst &CI);
Instruction *FoldSelectOpOp(SelectInst &SI, Instruction *TI,
@ -474,9 +474,16 @@ isEliminableCastPair(
Instruction::CastOps firstOp = Instruction::CastOps(CI->getOpcode());
Instruction::CastOps secondOp = Instruction::CastOps(opcode);
return Instruction::CastOps(
CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
DstTy, TD->getIntPtrType()));
unsigned Res = CastInst::isEliminableCastPair(firstOp, secondOp, SrcTy, MidTy,
DstTy, TD->getIntPtrType());
// We don't want to form an inttoptr or ptrtoint that converts to an integer
// type that differs from the pointer size.
if ((Res == Instruction::IntToPtr && SrcTy != TD->getIntPtrType()) ||
(Res == Instruction::PtrToInt && DstTy != TD->getIntPtrType()))
Res = 0;
return Instruction::CastOps(Res);
}
/// ValueRequiresCast - Return true if the cast from "V to Ty" actually results
@ -8536,11 +8543,36 @@ Instruction *InstCombiner::visitSIToFP(CastInst &CI) {
return commonCastTransforms(CI);
}
Instruction *InstCombiner::visitPtrToInt(CastInst &CI) {
Instruction *InstCombiner::visitPtrToInt(PtrToIntInst &CI) {
// If the destination integer type is smaller than the intptr_t type for
// this target, do a ptrtoint to intptr_t then do a trunc. This allows the
// trunc to be exposed to other transforms. Don't do this for extending
// ptrtoint's, because we don't know if the target sign or zero extends its
// pointers.
if (CI.getType()->getPrimitiveSizeInBits() < TD->getPointerSizeInBits()) {
Value *P = InsertNewInstBefore(new PtrToIntInst(CI.getOperand(0),
TD->getIntPtrType(),
"tmp"), CI);
return new TruncInst(P, CI.getType());
}
return commonPointerCastTransforms(CI);
}
Instruction *InstCombiner::visitIntToPtr(IntToPtrInst &CI) {
// If the source integer type is larger than the intptr_t type for
// this target, do a trunc to the intptr_t type, then inttoptr of it. This
// allows the trunc to be exposed to other transforms. Don't do this for
// extending inttoptr's, because we don't know if the target sign or zero
// extends to pointers.
if (CI.getOperand(0)->getType()->getPrimitiveSizeInBits() >
TD->getPointerSizeInBits()) {
Value *P = InsertNewInstBefore(new TruncInst(CI.getOperand(0),
TD->getIntPtrType(),
"tmp"), CI);
return new IntToPtrInst(P, CI.getType());
}
if (Instruction *I = commonCastTransforms(CI))
return I;

16
test/Transforms/InstCombine/ptr-int-cast.ll Normal file
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@ -0,0 +1,16 @@
; RUN: llvm-as < %s | opt -instcombine | llvm-dis > %t
define i1 @test1(i32 *%x) nounwind {
entry:
; RUN: grep {ptrtoint i32\\* %x to i64} %t
%tmp = ptrtoint i32* %x to i1
ret i1 %tmp
}
define i32* @test2(i128 %x) nounwind {
entry:
; RUN: grep {inttoptr i64 %.mp1 to i32\\*} %t
%tmp = inttoptr i128 %x to i32*
ret i32* %tmp
}