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Fix an off-by-one error in ctpop combining. 

llvm-svn: 123664
This commit is contained in:
Benjamin Kramer 2011-01-17 18:00:28 +00:00
parent 3ec1f198e5
commit 45d183ccf0
2 changed files with 12 additions and 3 deletions
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2
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
View File

@ -1876,7 +1876,7 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
CTPOP = N0.getOperand(0);
if (CTPOP.hasOneUse() && CTPOP.getOpcode() == ISD::CTPOP &&
(N0 == CTPOP || N0.getValueType().getSizeInBits() >=
(N0 == CTPOP || N0.getValueType().getSizeInBits() >
Log2_32_Ceil(CTPOP.getValueType().getSizeInBits()))) {
EVT CTVT = CTPOP.getValueType();
SDValue CTOp = CTPOP.getOperand(0);

13
llvm/test/CodeGen/X86/ctpop-combine.ll
View File

@ -18,8 +18,7 @@ define i32 @test1(i64 %x) nounwind readnone {
define i32 @test2(i64 %x) nounwind readnone {
%count = tail call i64 @llvm.ctpop.i64(i64 %x)
%cast = trunc i64 %count to i32
%cmp = icmp ult i32 %cast, 2
%cmp = icmp ult i64 %count, 2
%conv = zext i1 %cmp to i32
ret i32 %conv
; CHECK: test2:
@ -29,3 +28,13 @@ define i32 @test2(i64 %x) nounwind readnone {
; CHECK: ret
}
define i32 @test3(i64 %x) nounwind readnone {
%count = tail call i64 @llvm.ctpop.i64(i64 %x)
%cast = trunc i64 %count to i6 ; Too small for 0-64
%cmp = icmp ult i6 %cast, 2
%conv = zext i1 %cmp to i32
ret i32 %conv
; CHECK: test3:
; CHECK: cmpb $2
; CHECK: ret
}