[InstSimplify] generalize FP folds with undef/NaN; NFC

We can reuse this logic for things like fma.

llvm-svn: 373119

1 files changed, 14 insertions, 12 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 2a911a91e29..a2c622e7905 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4482,14 +4482,16 @@ static Constant *propagateNaN(Constant *In) {
   return In;
 }
 
-static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
-  if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
-    return ConstantFP::getNaN(Op0->getType());
+/// Perform folds that are common to any floating-point operation. This implies
+/// transforms based on undef/NaN because the operation itself makes no
+/// difference to the result.
+static Constant *simplifyFPOp(ArrayRef<Value *> Ops) {
+  if (any_of(Ops, [](Value *V) { return isa<UndefValue>(V); }))
+    return ConstantFP::getNaN(Ops[0]->getType());
 
-  if (match(Op0, m_NaN()))
-    return propagateNaN(cast<Constant>(Op0));
-  if (match(Op1, m_NaN()))
-    return propagateNaN(cast<Constant>(Op1));
+  for (Value *V : Ops)
+    if (match(V, m_NaN()))
+      return propagateNaN(cast<Constant>(V));
 
   return nullptr;
 }
@@ -4501,7 +4503,7 @@ static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
     return C;
 
-  if (Constant *C = simplifyFPBinop(Op0, Op1))
+  if (Constant *C = simplifyFPOp({Op0, Op1}))
     return C;
 
   // fadd X, -0 ==> X
@@ -4548,7 +4550,7 @@ static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
     return C;
 
-  if (Constant *C = simplifyFPBinop(Op0, Op1))
+  if (Constant *C = simplifyFPOp({Op0, Op1}))
     return C;
 
   // fsub X, +0 ==> X
@@ -4624,7 +4626,7 @@ static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
     return C;
 
-  if (Constant *C = simplifyFPBinop(Op0, Op1))
+  if (Constant *C = simplifyFPOp({Op0, Op1}))
     return C;
 
   // Now apply simplifications that do not require rounding.
@@ -4657,7 +4659,7 @@ static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
     return C;
 
-  if (Constant *C = simplifyFPBinop(Op0, Op1))
+  if (Constant *C = simplifyFPOp({Op0, Op1}))
     return C;
 
   // X / 1.0 -> X
@@ -4702,7 +4704,7 @@ static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
     return C;
 
-  if (Constant *C = simplifyFPBinop(Op0, Op1))
+  if (Constant *C = simplifyFPOp({Op0, Op1}))
     return C;
 
   // Unlike fdiv, the result of frem always matches the sign of the dividend.