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X86: Fix the (saddo/ssub x, 1) -> incl/decl selection to check the right operand for 1. 

Found by inspection.

llvm-svn: 127247
This commit is contained in:
Benjamin Kramer 2011-03-08 15:20:20 +00:00
parent 42e9aaa4b1
commit 679cfb54ec
3 changed files with 39 additions and 6 deletions
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8
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -8834,8 +8834,8 @@ SDValue X86TargetLowering::LowerXALUO(SDValue Op, SelectionDAG &DAG) const {
case ISD::SADDO:
// A subtract of one will be selected as a INC. Note that INC doesn't
// set CF, so we can't do this for UADDO.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
if (C->getAPIntValue() == 1) {
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS))
if (C->isOne()) {
BaseOp = X86ISD::INC;
Cond = X86::COND_O;
break;
@ -8850,8 +8850,8 @@ SDValue X86TargetLowering::LowerXALUO(SDValue Op, SelectionDAG &DAG) const {
case ISD::SSUBO:
// A subtract of one will be selected as a DEC. Note that DEC doesn't
// set CF, so we can't do this for USUBO.
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op))
if (C->getAPIntValue() == 1) {
if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS))
if (C->isOne()) {
BaseOp = X86ISD::DEC;
Cond = X86::COND_O;
break;

15
llvm/test/CodeGen/X86/add.ll
View File

@ -133,3 +133,18 @@ define i32 @test9(i32 %x, i32 %y) nounwind readnone {
; X64: subl
; X64: ret
}
define i1 @test10(i32 %x) nounwind {
entry:
%t = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %x, i32 1)
%obit = extractvalue {i32, i1} %t, 1
ret i1 %obit
; X32: test10:
; X32: incl
; X32-NEXT: seto
; X64: test10:
; X64: incl
; X64-NEXT: seto
}

22
llvm/test/CodeGen/X86/sub-with-overflow.ll
View File

@ -1,5 +1,4 @@
; RUN: llc < %s -march=x86 | grep {jo} | count 1
; RUN: llc < %s -march=x86 | grep {jb} | count 1
; RUN: llc < %s -march=x86 | FileCheck %s
@ok = internal constant [4 x i8] c"%d\0A\00"
@no = internal constant [4 x i8] c"no\0A\00"
@ -18,6 +17,10 @@ normal:
overflow:
%t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
ret i1 false
; CHECK: func1:
; CHECK: subl 20(%esp)
; CHECK-NEXT: jo
}
define i1 @func2(i32 %v1, i32 %v2) nounwind {
@ -34,8 +37,23 @@ normal:
carry:
%t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
ret i1 false
; CHECK: func2:
; CHECK: subl 20(%esp)
; CHECK-NEXT: jb
}
declare i32 @printf(i8*, ...) nounwind
declare {i32, i1} @llvm.ssub.with.overflow.i32(i32, i32)
declare {i32, i1} @llvm.usub.with.overflow.i32(i32, i32)
define i1 @func3(i32 %x) nounwind {
entry:
%t = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %x, i32 1)
%obit = extractvalue {i32, i1} %t, 1
ret i1 %obit
; CHECK: func3:
; CHECK: decl
; CHECK-NEXT: seto
}