Changes in directory llvm/lib/Target/X86:
X86ISelLowering.cpp updated: 1.34 -> 1.35
---
Log message:
Fix a SETCC / BRCOND folding bug.
---
Diffs of the changes: (+37 -12)
X86ISelLowering.cpp | 49 +++++++++++++++++++++++++++++++++++++------------
1 files changed, 37 insertions(+), 12 deletions(-)
Index: llvm/lib/Target/X86/X86ISelLowering.cpp
diff -u llvm/lib/Target/X86/X86ISelLowering.cpp:1.34
llvm/lib/Target/X86/X86ISelLowering.cpp:1.35
--- llvm/lib/Target/X86/X86ISelLowering.cpp:1.34 Thu Jan 12 16:54:21 2006
+++ llvm/lib/Target/X86/X86ISelLowering.cpp Thu Jan 12 19:03:02 2006
@@ -1572,14 +1572,24 @@
bool isFP = MVT::isFloatingPoint(VT);
bool isFPStack = isFP && (X86Vector < SSE2);
bool isFPSSE = isFP && (X86Vector >= SSE2);
- bool isValid = false;
+ bool addTest = false;
SDOperand Op0 = Op.getOperand(0);
SDOperand Cond, CC;
if (Op0.getOpcode() == X86ISD::SETCC) {
- CC = Op0.getOperand(0);
- Cond = Op0.getOperand(1);
- isValid =
- !(isFPStack &&
!hasFPCMov(cast<ConstantSDNode>(CC)->getSignExtended()));
+ // If condition flag is set by a X86ISD::CMP, then make a copy of it
+ // (since flag operand cannot be shared). If the X86ISD::SETCC does not
+ // have another use it will be eliminated.
+ // If the X86ISD::SETCC has more than one use, then it's probably better
+ // to use a test instead of duplicating the X86ISD::CMP (for register
+ // pressure reason).
+ if (Cond.hasOneUse() && Cond.getOperand(1).getOpcode() == X86ISD::CMP) {
+ CC = Op0.getOperand(0);
+ Cond = Op0.getOperand(1);
+ addTest =
+ !(isFPStack &&
+ !hasFPCMov(cast<ConstantSDNode>(CC)->getSignExtended()));
+ } else
+ addTest = true;
} else if (Op0.getOpcode() == ISD::SETCC) {
CC = Op0.getOperand(2);
bool isFP = MVT::isFloatingPoint(Op0.getOperand(1).getValueType());
@@ -1587,10 +1597,11 @@
CC = DAG.getConstant(X86CC, MVT::i8);
Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
Op0.getOperand(0), Op0.getOperand(1));
- isValid = true;
- }
+ addTest = true;
+ } else
+ addTest = true;
- if (!isValid) {
+ if (!addTest) {
CC = DAG.getConstant(X86ISD::COND_E, MVT::i8);
Cond = DAG.getNode(X86ISD::TEST, MVT::Flag, Op0, Op0);
}
@@ -1606,13 +1617,24 @@
return DAG.getNode(X86ISD::CMOV, Tys, Ops);
}
case ISD::BRCOND: {
+ bool addTest = false;
SDOperand Cond = Op.getOperand(1);
SDOperand Dest = Op.getOperand(2);
SDOperand CC;
- // TODO: handle Cond == OR / AND / XOR
if (Cond.getOpcode() == X86ISD::SETCC) {
- CC = Cond.getOperand(0);
- Cond = Cond.getOperand(1);
+ // If condition flag is set by a X86ISD::CMP, then make a copy of it
+ // (since flag operand cannot be shared). If the X86ISD::SETCC does not
+ // have another use it will be eliminated.
+ // If the X86ISD::SETCC has more than one use, then it's probably better
+ // to use a test instead of duplicating the X86ISD::CMP (for register
+ // pressure reason).
+ if (Cond.hasOneUse() && Cond.getOperand(1).getOpcode() == X86ISD::CMP) {
+ CC = Cond.getOperand(0);
+ Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
+ Cond.getOperand(1).getOperand(0),
+ Cond.getOperand(1).getOperand(1));
+ } else
+ addTest = true;
} else if (Cond.getOpcode() == ISD::SETCC) {
CC = Cond.getOperand(2);
bool isFP = MVT::isFloatingPoint(Cond.getOperand(1).getValueType());
@@ -1620,7 +1642,10 @@
CC = DAG.getConstant(X86CC, MVT::i8);
Cond = DAG.getNode(X86ISD::CMP, MVT::Flag,
Cond.getOperand(0), Cond.getOperand(1));
- } else {
+ } else
+ addTest = true;
+
+ if (addTest) {
CC = DAG.getConstant(X86ISD::COND_NE, MVT::i8);
Cond = DAG.getNode(X86ISD::TEST, MVT::Flag, Cond, Cond);
}
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