[llvm-commits] [llvm] r54752 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/FrontendAda/constant_fold.ads
Duncan Sands
baldrick at free.fr
Wed Aug 13 13:20:35 PDT 2008
Author: baldrick
Date: Wed Aug 13 15:20:35 2008
New Revision: 54752
URL: http://llvm.org/viewvc/llvm-project?rev=54752&view=rev
Log:
Teach constant folding that an inttoptr of a
ptrtoint can be turned into a bitcast if the
integer is at least as wide as a pointer.
Added:
llvm/trunk/test/FrontendAda/constant_fold.ads
Modified:
llvm/trunk/lib/Analysis/ConstantFolding.cpp
Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=54752&r1=54751&r2=54752&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Wed Aug 13 15:20:35 2008
@@ -378,6 +378,19 @@
}
return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::IntToPtr:
+ // If the input is a ptrtoint, turn the pair into a ptr to ptr bitcast if
+ // the int size is >= the ptr size. This requires knowing the width of a
+ // pointer, so it can't be done in ConstantExpr::getCast.
+ if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ops[0])) {
+ if (TD && CE->getOpcode() == Instruction::PtrToInt &&
+ TD->getPointerSizeInBits() <=
+ CE->getType()->getPrimitiveSizeInBits()) {
+ Constant *Input = CE->getOperand(0);
+ Constant *C = FoldBitCast(Input, DestTy, *TD);
+ return C ? C : ConstantExpr::getBitCast(Input, DestTy);
+ }
+ }
+ return ConstantExpr::getCast(Opcode, Ops[0], DestTy);
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
Added: llvm/trunk/test/FrontendAda/constant_fold.ads
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/FrontendAda/constant_fold.ads?rev=54752&view=auto
==============================================================================
--- llvm/trunk/test/FrontendAda/constant_fold.ads (added)
+++ llvm/trunk/test/FrontendAda/constant_fold.ads Wed Aug 13 15:20:35 2008
@@ -0,0 +1,4 @@
+-- RUN: %llvmgcc -S -emit-llvm %s -o - | not grep ptrtoint
+package Constant_Fold is
+ Error : exception;
+end;
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