// to explicitly materialize a constant.
const ConstantFP *FPImm = getConstantFPVRegVal(RHS, MRI);
bool ShouldUseImm = FPImm && (FPImm->isZero() && !FPImm->isNegative());
+ if (!ShouldUseImm) {
+ // Try commutating the operands.
+ const ConstantFP *LHSImm = getConstantFPVRegVal(LHS, MRI);
+ if (LHSImm && (LHSImm->isZero() && !LHSImm->isNegative())) {
+ ShouldUseImm = true;
+ std::swap(LHS, RHS);
+ }
+ }
unsigned CmpOpcTbl[2][2] = {{AArch64::FCMPSrr, AArch64::FCMPDrr},
{AArch64::FCMPSri, AArch64::FCMPDri}};
unsigned CmpOpc = CmpOpcTbl[ShouldUseImm][OpSize == 64];
%3:gpr(s32) = G_FCMP floatpred(oeq), %0(s64), %2
$s0 = COPY %3(s32)
RET_ReallyLR implicit $s0
+...
+
+---
+name: zero_lhs
+alignment: 4
+legalized: true
+regBankSelected: true
+tracksRegLiveness: true
+body: |
+ bb.1:
+ liveins: $s0, $s1
+
+ ; CHECK-LABEL: name: zero_lhs
+ ; CHECK: liveins: $s0, $s1
+ ; CHECK: [[COPY:%[0-9]+]]:fpr32 = COPY $s0
+ ; CHECK: FCMPSri [[COPY]], implicit-def $nzcv
+ ; CHECK: [[CSINCWr:%[0-9]+]]:gpr32 = CSINCWr $wzr, $wzr, 1, implicit $nzcv
+ ; CHECK: $s0 = COPY [[CSINCWr]]
+ ; CHECK: RET_ReallyLR implicit $s0
+ %0:fpr(s32) = COPY $s0
+ %1:fpr(s32) = COPY $s1
+ %2:fpr(s32) = G_FCONSTANT float 0.000000e+00
+ %3:gpr(s32) = G_FCMP floatpred(oeq), %2(s32), %0
+ $s0 = COPY %3(s32)
+ RET_ReallyLR implicit $s0
+
+...