diff --git a/llvm/include/llvm/IR/Instruction.h b/llvm/include/llvm/IR/Instruction.h
--- a/llvm/include/llvm/IR/Instruction.h
+++ b/llvm/include/llvm/IR/Instruction.h
@@ -495,6 +495,10 @@
   /// V and this instruction.
   void andIRFlags(const Value *V);
 
+  /// Logical 'and' of non poison generating flags, like fast-math flags, of
+  /// V and this instruction.
+  void andNonPoisonGeneratingIRFlags(const Value *V);
+
   /// Merge 2 debug locations and apply it to the Instruction. If the
   /// instruction is a CallIns, we need to traverse the inline chain to find
   /// the common scope. This is not efficient for N-way merging as each time
diff --git a/llvm/lib/IR/Instruction.cpp b/llvm/lib/IR/Instruction.cpp
--- a/llvm/lib/IR/Instruction.cpp
+++ b/llvm/lib/IR/Instruction.cpp
@@ -316,6 +316,16 @@
       DestGEP->setIsInBounds(SrcGEP->isInBounds() || DestGEP->isInBounds());
 }
 
+void Instruction::andNonPoisonGeneratingIRFlags(const Value *V) {
+  if (auto *FP = dyn_cast<FPMathOperator>(V)) {
+    if (isa<FPMathOperator>(this)) {
+      FastMathFlags FM = getFastMathFlags();
+      FM &= FP->getFastMathFlags();
+      copyFastMathFlags(FM);
+    }
+  }
+}
+
 void Instruction::andIRFlags(const Value *V) {
   if (auto *OB = dyn_cast<OverflowingBinaryOperator>(V)) {
     if (isa<OverflowingBinaryOperator>(this)) {
@@ -328,17 +338,11 @@
     if (isa<PossiblyExactOperator>(this))
       setIsExact(isExact() && PE->isExact());
 
-  if (auto *FP = dyn_cast<FPMathOperator>(V)) {
-    if (isa<FPMathOperator>(this)) {
-      FastMathFlags FM = getFastMathFlags();
-      FM &= FP->getFastMathFlags();
-      copyFastMathFlags(FM);
-    }
-  }
-
   if (auto *SrcGEP = dyn_cast<GetElementPtrInst>(V))
     if (auto *DestGEP = dyn_cast<GetElementPtrInst>(this))
       DestGEP->setIsInBounds(SrcGEP->isInBounds() && DestGEP->isInBounds());
+
+  andNonPoisonGeneratingIRFlags(V);
 }
 
 const char *Instruction::getOpcodeName(unsigned OpCode) {