Author: lattner
Date: Sat Aug 11 18:49:01 2007
New Revision: 41023
URL: http://llvm.org/viewvc/llvm-project?rev=41023&view=rev
Log:
constant fold ptrtoint(inttoptr) with target data when available. This allows
us to fold the entry block of PR1602 to false instead of:
br i1 icmp eq (i32 and (i32 ptrtoint (void (%struct.S*)* inttoptr (i64
1 to void (%struct.S*)*) to i32), i32 1), i32 0), label %cond_next, label
%cond_true
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=41023&r1=41022&r2=41023&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Sat Aug 11 18:49:01 2007
@@ -217,6 +217,23 @@
case Instruction::FCmp:
return ConstantExpr::getCompare(cast<CmpInst>(I)->getPredicate(), Ops[0],
Ops[1]);
+ case Instruction::PtrToInt:
+ // If the input is a inttoptr, eliminate the pair. 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::IntToPtr) {
+ Constant *Input = CE->getOperand(0);
+ unsigned InWidth = Input->getType()->getPrimitiveSizeInBits();
+ Constant *Mask =
+ ConstantInt::get(APInt::getLowBitsSet(InWidth,
+ TD->getPointerSizeInBits()));
+ Input = ConstantExpr::getAnd(Input, Mask);
+ // Do a zext or trunc to get to the dest size.
+ return ConstantExpr::getIntegerCast(Input, I->getType(), false);
+ }
+ }
+ // FALL THROUGH.
+ case Instruction::IntToPtr:
case Instruction::Trunc:
case Instruction::ZExt:
case Instruction::SExt:
@@ -226,8 +243,6 @@
case Instruction::SIToFP:
case Instruction::FPToUI:
case Instruction::FPToSI:
- case Instruction::PtrToInt:
- case Instruction::IntToPtr:
case Instruction::BitCast:
return ConstantExpr::getCast(Opc, Ops[0], DestTy);
case Instruction::Select:
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