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Transform (xor (setcc), (setcc)) == / != 1 to

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(xor (setcc), (setcc)) != / == 1.

e.g. On x86_64
  %0 = icmp eq i32 %x, 0
  %1 = icmp eq i32 %y, 0
  %2 = xor i1 %1, %0
  br i1 %2, label %bb, label %return
=>
	testl   %edi, %edi
	sete    %al
	testl   %esi, %esi
	sete    %cl
	cmpb    %al, %cl
	je      LBB1_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96640 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-02-19 00:34:39 +00:00
parent 853b919d93
commit 97a35fc3a7
2 changed files with 44 additions and 3 deletions
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16
lib/CodeGen/SelectionDAG/TargetLowering.cpp
View File

@ -1855,9 +1855,19 @@ TargetLowering::SimplifySetCC(EVT VT, SDValue N0, SDValue N1,
SDValue Op0 = N0;
if (Op0.getOpcode() == ISD::TRUNCATE)
Op0 = Op0.getOperand(0);
if (Op0.getOpcode() == ISD::AND &&
isa<ConstantSDNode>(Op0.getOperand(1)) &&
cast<ConstantSDNode>(Op0.getOperand(1))->getAPIntValue() == 1) {
if ((Op0.getOpcode() == ISD::XOR || Op0.getOpcode() == ISD::AND) &&
Op0.getOperand(0).getOpcode() == ISD::SETCC &&
Op0.getOperand(1).getOpcode() == ISD::SETCC) {
// (and (setcc), (setcc)) == / != 1 -> (setcc) == / != (setcc)
// (xor (setcc), (setcc)) == / != 1 -> (setcc) != / == (setcc)
if (Op0.getOpcode() == ISD::XOR)
Cond = (Cond == ISD::SETEQ) ? ISD::SETNE : ISD::SETEQ;
return DAG.getSetCC(dl, VT, Op0.getOperand(0), Op0.getOperand(1),
Cond);
} else if (Op0.getOpcode() == ISD::AND &&
isa<ConstantSDNode>(Op0.getOperand(1)) &&
cast<ConstantSDNode>(Op0.getOperand(1))->getAPIntValue() == 1) {
if (Op0.getValueType() != VT)
Op0 = DAG.getNode(ISD::AND, dl, VT,
DAG.getNode(ISD::TRUNCATE, dl, VT, Op0.getOperand(0)),

31
test/CodeGen/X86/xor-icmp.ll
View File

@ -1,5 +1,6 @@
; RUN: llc < %s -march=x86 | FileCheck %s -check-prefix=X32
; RUN: llc < %s -march=x86-64 | FileCheck %s -check-prefix=X64
; rdar://7367229
define i32 @t(i32 %a, i32 %b) nounwind ssp {
entry:
@ -34,3 +35,33 @@ bb1: ; preds = %entry
declare i32 @foo(...)
declare i32 @bar(...)
define i32 @t2(i32 %x, i32 %y) nounwind ssp {
; X32: t2:
; X32: cmpl
; X32: sete
; X32: cmpl
; X32: sete
; X32-NOT: xor
; X32: je
; X64: t2:
; X64: testl
; X64: sete
; X64: testl
; X64: sete
; X64-NOT: xor
; X64: je
entry:
%0 = icmp eq i32 %x, 0 ; <i1> [#uses=1]
%1 = icmp eq i32 %y, 0 ; <i1> [#uses=1]
%2 = xor i1 %1, %0 ; <i1> [#uses=1]
br i1 %2, label %bb, label %return
bb: ; preds = %entry
%3 = tail call i32 (...)* @foo() nounwind ; <i32> [#uses=0]
ret i32 undef
return: ; preds = %entry
ret i32 undef
}