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ConstantFolding: Fix a crash when encoutering a truncating inttoptr. 

This was introduced in r173293.

llvm-svn: 174424
This commit is contained in:
Benjamin Kramer 2013-02-05 19:04:36 +00:00
parent 3be40b56c5
commit a5a9ec5755
2 changed files with 26 additions and 3 deletions
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10
llvm/lib/Analysis/ConstantFolding.cpp
View File

@ -545,14 +545,18 @@ static Constant *SymbolicallyEvaluateBinop(unsigned Opc, Constant *Op0,
// constant. This happens frequently when iterating over a global array. // constant. This happens frequently when iterating over a global array.
if (Opc == Instruction::Sub && TD) { if (Opc == Instruction::Sub && TD) {
GlobalValue *GV1, *GV2; GlobalValue *GV1, *GV2;
APInt Offs1(TD->getPointerSizeInBits(), 0), unsigned PtrSize = TD->getPointerSizeInBits();
Offs2(TD->getPointerSizeInBits(), 0); unsigned OpSize = TD->getTypeSizeInBits(Op0->getType());
APInt Offs1(PtrSize, 0), Offs2(PtrSize, 0);
if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD)) if (IsConstantOffsetFromGlobal(Op0, GV1, Offs1, *TD))
if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) && if (IsConstantOffsetFromGlobal(Op1, GV2, Offs2, *TD) &&
GV1 == GV2) { GV1 == GV2) {
// (&GV+C1) - (&GV+C2) -> C1-C2, pointer arithmetic cannot overflow. // (&GV+C1) - (&GV+C2) -> C1-C2, pointer arithmetic cannot overflow.
return ConstantInt::get(Op0->getType(), Offs1-Offs2); // PtrToInt may change the bitwidth so we have convert to the right size
// first.
return ConstantInt::get(Op0->getType(), Offs1.zextOrTrunc(OpSize) -
Offs2.zextOrTrunc(OpSize));
} }
} }

19
llvm/test/Transforms/InstSimplify/ptr_diff.ll
View File

@ -57,3 +57,22 @@ define <4 x i32> @ptrdiff4(<4 x i8*> %arg) nounwind {
%sub = sub <4 x i32> %p1, %p2 %sub = sub <4 x i32> %p1, %p2
ret <4 x i32> %sub ret <4 x i32> %sub
} }
%struct.ham = type { i32, [2 x [2 x i32]] }
@global = internal global %struct.ham zeroinitializer, align 4
define i32 @ptrdiff5() nounwind {
bb:
%tmp = getelementptr inbounds %struct.ham* @global, i32 0, i32 1
%tmp1 = getelementptr inbounds [2 x [2 x i32]]* %tmp, i32 0, i32 0
%tmp2 = bitcast [2 x i32]* %tmp1 to i32*
%tmp3 = ptrtoint i32* %tmp2 to i32
%tmp4 = getelementptr inbounds %struct.ham* @global, i32 0, i32 1
%tmp5 = getelementptr inbounds [2 x [2 x i32]]* %tmp4, i32 0, i32 0
%tmp6 = ptrtoint [2 x i32]* %tmp5 to i32
%tmp7 = sub i32 %tmp3, %tmp6
ret i32 %tmp7
; CHECK: @ptrdiff5
; CHECK: ret i32 0
}