[RISCV] Avoid illegal DAG combination for strict-fp nodes.

Those combines may change the exception behavior and rounding behavior.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D151992

Author: Yeting Kuo

llvm/lib/Target/RISCV/RISCVISelLowering.cpp

@@ -11138,6 +11138,10 @@ static SDValue performFP_TO_INTCombine(SDNode *N,
 
   SDValue Src = N->getOperand(0);
 
+  // Don't do this for strict-fp Src.
+  if (Src->isStrictFPOpcode() || Src->isTargetStrictFPOpcode())
+    return SDValue();
+
   // Ensure the FP type is legal.
   if (!TLI.isTypeLegal(Src.getValueType()))
     return SDValue();
@@ -11237,6 +11241,10 @@ static SDValue performFP_TO_INT_SATCombine(SDNode *N,
 
   SDValue Src = N->getOperand(0);
 
+  // Don't do this for strict-fp Src.
+  if (Src->isStrictFPOpcode() || Src->isTargetStrictFPOpcode())
+    return SDValue();
+
   // Ensure the FP type is also legal.
   if (!TLI.isTypeLegal(Src.getValueType()))
     return SDValue();