[InstSimplify] move minnum/maxnum with undef fold from instcombine

llvm-svn: 338719

2 files changed, 4 insertions, 14 deletions

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index b1601bfe1b2..ffdbfc45c84 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4767,9 +4767,10 @@ static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
     // If the arguments are the same, this is a no-op.
     if (Op0 == Op1) return Op0;
 
-    // If one argument is NaN, return the other argument.
-    if (match(Op0, m_NaN())) return Op1;
-    if (match(Op1, m_NaN())) return Op0;
+    // If one argument is NaN or undef, return the other argument.
+    if (match(Op0, m_CombineOr(m_NaN(), m_Undef()))) return Op1;
+    if (match(Op1, m_CombineOr(m_NaN(), m_Undef()))) return Op0;
+
     break;
   default:
     break;
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 77c5a06ee11..748cb97d9b5 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1143,17 +1143,6 @@ static Value *simplifyMinnumMaxnum(const IntrinsicInst &II) {
   if (C1 && C1->isNaN())
     return Arg0;
 
-  // This is the value because if undef were NaN, we would return the other
-  // value and cannot return a NaN unless both operands are.
-  //
-  // fmin(undef, x) -> x
-  if (isa<UndefValue>(Arg0))
-    return Arg1;
-
-  // fmin(x, undef) -> x
-  if (isa<UndefValue>(Arg1))
-    return Arg0;
-
   Value *X = nullptr;
   Value *Y = nullptr;
   if (II.getIntrinsicID() == Intrinsic::minnum) {