Neuter the optimization I implemented with r107852 and r108258 which turn some
floating point equality comparisons into integer ones with -ffast-math. The
issue is the optimization causes +0.0 != -0.0.
Now the optimization is only done when one side is known to be 0.0. The other
side's sign bit is masked off for the comparison.
rdar://10964603
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151861 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index 8ad7136..0ca9704 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -2978,12 +2978,11 @@
SDValue Dest = Op.getOperand(4);
DebugLoc dl = Op.getDebugLoc();
- bool SeenZero = false;
- if (canChangeToInt(LHS, SeenZero, Subtarget) &&
- canChangeToInt(RHS, SeenZero, Subtarget) &&
- // If one of the operand is zero, it's safe to ignore the NaN case since
- // we only care about equality comparisons.
- (SeenZero || (DAG.isKnownNeverNaN(LHS) && DAG.isKnownNeverNaN(RHS)))) {
+ bool LHSSeenZero = false;
+ bool LHSOk = canChangeToInt(LHS, LHSSeenZero, Subtarget);
+ bool RHSSeenZero = false;
+ bool RHSOk = canChangeToInt(RHS, RHSSeenZero, Subtarget);
+ if (LHSOk && RHSOk && (LHSSeenZero || RHSSeenZero)) {
// If unsafe fp math optimization is enabled and there are no other uses of
// the CMP operands, and the condition code is EQ or NE, we can optimize it
// to an integer comparison.
@@ -2992,10 +2991,13 @@
else if (CC == ISD::SETUNE)
CC = ISD::SETNE;
+ SDValue Mask = DAG.getConstant(0x7fffffff, MVT::i32);
SDValue ARMcc;
if (LHS.getValueType() == MVT::f32) {
- LHS = bitcastf32Toi32(LHS, DAG);
- RHS = bitcastf32Toi32(RHS, DAG);
+ LHS = DAG.getNode(ISD::AND, dl, MVT::i32,
+ bitcastf32Toi32(LHS, DAG), Mask);
+ RHS = DAG.getNode(ISD::AND, dl, MVT::i32,
+ bitcastf32Toi32(RHS, DAG), Mask);
SDValue Cmp = getARMCmp(LHS, RHS, CC, ARMcc, DAG, dl);
SDValue CCR = DAG.getRegister(ARM::CPSR, MVT::i32);
return DAG.getNode(ARMISD::BRCOND, dl, MVT::Other,
@@ -3006,6 +3008,8 @@
SDValue RHS1, RHS2;
expandf64Toi32(LHS, DAG, LHS1, LHS2);
expandf64Toi32(RHS, DAG, RHS1, RHS2);
+ LHS2 = DAG.getNode(ISD::AND, dl, MVT::i32, LHS2, Mask);
+ RHS2 = DAG.getNode(ISD::AND, dl, MVT::i32, RHS2, Mask);
ARMCC::CondCodes CondCode = IntCCToARMCC(CC);
ARMcc = DAG.getConstant(CondCode, MVT::i32);
SDVTList VTList = DAG.getVTList(MVT::Other, MVT::Glue);