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X86: when replacing SUB with TEST in ISelDAGToDAG, only replace uses of the

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second output of SUB with first output of TEST.

PR13966


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164835 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Manman Ren
2012-09-28 18:53:24 +00:00
parent 770b97b995
commit bc96bcdaf9
1 changed files with 28 additions and 5 deletions
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33
lib/Target/X86/X86ISelDAGToDAG.cpp
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@@ -2525,7 +2525,13 @@ SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
MVT::i8, Reg); MVT::i8, Reg);
// Emit a testb. // Emit a testb.
return CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32, Subreg, Imm); SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32,
Subreg, Imm);
// Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
// one, do not call ReplaceAllUsesWith.
ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
SDValue(NewNode, 0));
return NULL;
} }
// For example, "testl %eax, $2048" to "testb %ah, $8". // For example, "testl %eax, $2048" to "testb %ah, $8".
@@ -2556,8 +2562,13 @@ SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
// Emit a testb. The EXTRACT_SUBREG becomes a COPY that can only // Emit a testb. The EXTRACT_SUBREG becomes a COPY that can only
// target GR8_NOREX registers, so make sure the register class is // target GR8_NOREX registers, so make sure the register class is
// forced. // forced.
return CurDAG->getMachineNode(X86::TEST8ri_NOREX, dl, MVT::i32, SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri_NOREX, dl,
Subreg, ShiftedImm); MVT::i32, Subreg, ShiftedImm);
// Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
// one, do not call ReplaceAllUsesWith.
ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
SDValue(NewNode, 0));
return NULL;
} }
// For example, "testl %eax, $32776" to "testw %ax, $32776". // For example, "testl %eax, $32776" to "testw %ax, $32776".
@@ -2573,7 +2584,13 @@ SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
MVT::i16, Reg); MVT::i16, Reg);
// Emit a testw. // Emit a testw.
return CurDAG->getMachineNode(X86::TEST16ri, dl, MVT::i32, Subreg, Imm); SDNode *NewNode = CurDAG->getMachineNode(X86::TEST16ri, dl, MVT::i32,
Subreg, Imm);
// Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
// one, do not call ReplaceAllUsesWith.
ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
SDValue(NewNode, 0));
return NULL;
} }
// For example, "testq %rax, $268468232" to "testl %eax, $268468232". // For example, "testq %rax, $268468232" to "testl %eax, $268468232".
@@ -2589,7 +2606,13 @@ SDNode *X86DAGToDAGISel::Select(SDNode *Node) {
MVT::i32, Reg); MVT::i32, Reg);
// Emit a testl. // Emit a testl.
return CurDAG->getMachineNode(X86::TEST32ri, dl, MVT::i32, Subreg, Imm); SDNode *NewNode = CurDAG->getMachineNode(X86::TEST32ri, dl, MVT::i32,
Subreg, Imm);
// Replace SUB|CMP with TEST, since SUB has two outputs while TEST has
// one, do not call ReplaceAllUsesWith.
ReplaceUses(SDValue(Node, (Opcode == X86ISD::SUB ? 1 : 0)),
SDValue(NewNode, 0));
return NULL;
} }
} }
break; break;