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[SelectionDAG] Fixed issue with uitofp vector constant folding being treated as sitofp 

While the uitofp scalar constant folding treats an integer as an unsigned value (from lang ref):

%X = sitofp i8 -1 to double ; yields double:-1.0
%Y = uitofp i8 -1 to double ; yields double:255.0

The vector constant folding was always using sitofp:

%X = sitofp <2 x i8> <i8 -1, i8 -1> to <2 x double> ; yields <double -1.0, double -1.0>
%Y = uitofp <2 x i8> <i8 -1, i8 -1> to <2 x double> ; yields <double -1.0, double -1.0>

This patch fixes this so that the correct opcode is used for sitofp and uitofp.

%X = sitofp <2 x i8> <i8 -1, i8 -1> to <2 x double> ; yields <double -1.0, double -1.0>
%Y = uitofp <2 x i8> <i8 -1, i8 -1> to <2 x double> ; yields <double 255.0, double 255.0>

Differential Revision: http://reviews.llvm.org/D8560

llvm-svn: 233033
This commit is contained in:
Simon Pilgrim 2015-03-23 22:44:55 +00:00
parent 735e87ea75
commit 481f4146cd
2 changed files with 17 additions and 4 deletions
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6
llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -2837,13 +2837,11 @@ SDValue SelectionDAG::getNode(unsigned Opcode, SDLoc DL,
break; break;
case ISD::UINT_TO_FP: case ISD::UINT_TO_FP:
case ISD::SINT_TO_FP: { case ISD::SINT_TO_FP: {
// Let the above scalar folding handle the folding of each element.
SmallVector<SDValue, 8> Ops; SmallVector<SDValue, 8> Ops;
for (int i = 0, e = VT.getVectorNumElements(); i != e; ++i) { for (int i = 0, e = VT.getVectorNumElements(); i != e; ++i) {
SDValue OpN = BV->getOperand(i); SDValue OpN = BV->getOperand(i);
// Let the above scalar folding handle the conversion of each OpN = getNode(Opcode, DL, VT.getVectorElementType(), OpN);
// element.
OpN = getNode(ISD::SINT_TO_FP, DL, VT.getVectorElementType(),
OpN);
Ops.push_back(OpN); Ops.push_back(OpN);
} }
return getNode(ISD::BUILD_VECTOR, DL, VT, Ops); return getNode(ISD::BUILD_VECTOR, DL, VT, Ops);

15
llvm/test/CodeGen/X86/x86-setcc-int-to-fp-combine.ll
View File

@ -72,3 +72,18 @@ define <4 x float> @foo3(<4 x float> %val, <4 x float> %test) nounwind {
%result = sitofp <4 x i32> %and to <4 x float> %result = sitofp <4 x i32> %and to <4 x float>
ret <4 x float> %result ret <4 x float> %result
} }
; Test the general purpose constant folding of uint->fp.
define void @foo4(<4 x float>* noalias %result) nounwind {
; CHECK-LABEL: LCPI4_0:
; CHECK-NEXT: .long 1065353216 ## float 1.000000e+00
; CHECK-NEXT: .long 1123942400 ## float 1.270000e+02
; CHECK-NEXT: .long 1124073472 ## float 1.280000e+02
; CHECK-NEXT: .long 1132396544 ## float 2.550000e+02
; CHECK-LABEL: foo4:
; CHECK: movaps LCPI4_0(%rip), %xmm0
%val = uitofp <4 x i8> <i8 1, i8 127, i8 -128, i8 -1> to <4 x float>
store <4 x float> %val, <4 x float>* %result
ret void
}