fix PR13577, an issue introduced by r161687

- FCMOV only supports a subset of X86 conditions. Skip boolean
  simplification if X86 condition is not valid for FCMOV.
- add a minimal test case for PR13577.

llvm-svn: 161732

1 files changed, 19 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index af1675b4d94..5dbe633d6e8 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -13843,6 +13843,22 @@ static SDValue BoolTestSetCCCombine(SDValue Cmp, X86::CondCode &CC) {
   return SetCC.getOperand(1);
 }
 
+static bool IsValidFCMOVCondition(X86::CondCode CC) {
+  switch (CC) {
+  default:
+    return false;
+  case X86::COND_B:
+  case X86::COND_BE:
+  case X86::COND_E:
+  case X86::COND_P:
+  case X86::COND_AE:
+  case X86::COND_A:
+  case X86::COND_NE:
+  case X86::COND_NP:
+    return true;
+  }
+}
+
 /// Optimize X86ISD::CMOV [LHS, RHS, CONDCODE (e.g. X86::COND_NE), CONDVAL]
 static SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG,
                                   TargetLowering::DAGCombinerInfo &DCI) {
@@ -13871,7 +13887,9 @@ static SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG,
   SDValue Flags;
 
   Flags = BoolTestSetCCCombine(Cond, CC);
-  if (Flags.getNode()) {
+  if (Flags.getNode() &&
+      // Extra check as FCMOV only supports a subset of X86 cond.
+      (FalseOp.getValueType() != MVT::f80 || IsValidFCMOVCondition(CC))) {
     SDValue Ops[] = { FalseOp, TrueOp,
                       DAG.getConstant(CC, MVT::i8), Flags };
     return DAG.getNode(X86ISD::CMOV, DL, N->getVTList(),