diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -4807,12 +4807,16 @@
 }
 
 /// Perform folds that are common to any floating-point operation. This implies
-/// transforms based on undef/NaN because the operation itself makes no
+/// transforms based on poison/undef/NaN because the operation itself makes no
 /// difference to the result.
-static Constant *simplifyFPOp(ArrayRef<Value *> Ops,
-                              FastMathFlags FMF,
+static Constant *simplifyFPOp(ArrayRef<Value *> Ops, FastMathFlags FMF,
                               const SimplifyQuery &Q) {
   for (Value *V : Ops) {
+    // Poison is independent of anything else. It always propagates from an
+    // operand to a math result.
+    if (match(V, m_Poison()))
+      return PoisonValue::get(V->getType());
+
     bool IsNan = match(V, m_NaN());
     bool IsInf = match(V, m_Inf());
     bool IsUndef = Q.isUndefValue(V);
diff --git a/llvm/test/Transforms/InstSimplify/call.ll b/llvm/test/Transforms/InstSimplify/call.ll
--- a/llvm/test/Transforms/InstSimplify/call.ll
+++ b/llvm/test/Transforms/InstSimplify/call.ll
@@ -953,7 +953,7 @@
 
 define double @fma_poison_op0(double %x, double %y) {
 ; CHECK-LABEL: @fma_poison_op0(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fma.f64(double poison, double %x, double %y)
   ret double %r
@@ -969,7 +969,7 @@
 
 define double @fma_poison_op1(double %x, double %y) {
 ; CHECK-LABEL: @fma_poison_op1(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fma.f64(double %x, double poison, double %y)
   ret double %r
@@ -985,7 +985,7 @@
 
 define double @fma_poison_op2(double %x, double %y) {
 ; CHECK-LABEL: @fma_poison_op2(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fma.f64(double %x, double %y, double poison)
   ret double %r
@@ -1001,7 +1001,7 @@
 
 define double @fmuladd_poison_op0(double %x, double %y) {
 ; CHECK-LABEL: @fmuladd_poison_op0(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fmuladd.f64(double poison, double %x, double %y)
   ret double %r
@@ -1017,7 +1017,7 @@
 
 define double @fmuladd_poison_op1(double %x, double %y) {
 ; CHECK-LABEL: @fmuladd_poison_op1(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fmuladd.f64(double %x, double poison, double %y)
   ret double %r
@@ -1033,7 +1033,7 @@
 
 define double @fmuladd_poison_op2(double %x, double %y) {
 ; CHECK-LABEL: @fmuladd_poison_op2(
-; CHECK-NEXT:    ret double 0x7FF8000000000000
+; CHECK-NEXT:    ret double poison
 ;
   %r = call double @llvm.fmuladd.f64(double %x, double %y, double poison)
   ret double %r
diff --git a/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll b/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll
--- a/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll
+++ b/llvm/test/Transforms/InstSimplify/fp-undef-poison.ll
@@ -1,8 +1,6 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
 ; RUN: opt < %s -instsimplify -S | FileCheck %s
 
-; TODO: the instructions with poison operands should return poison
-
 define float @fadd_undef_op0(float %x) {
 ; CHECK-LABEL: @fadd_undef_op0(
 ; CHECK-NEXT:    ret float 0x7FF8000000000000
@@ -13,7 +11,7 @@
 
 define float @fadd_poison_op0(float %x) {
 ; CHECK-LABEL: @fadd_poison_op0(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fadd float poison, %x
   ret float %r
@@ -29,7 +27,7 @@
 
 define float @fadd_poison_op1(float %x) {
 ; CHECK-LABEL: @fadd_poison_op1(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fadd float %x, poison
   ret float %r
@@ -45,7 +43,7 @@
 
 define float @fsub_poison_op0(float %x) {
 ; CHECK-LABEL: @fsub_poison_op0(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fsub float poison, %x
   ret float %r
@@ -61,7 +59,7 @@
 
 define float @fsub_poison_op1(float %x) {
 ; CHECK-LABEL: @fsub_poison_op1(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fsub float %x, poison
   ret float %r
@@ -77,7 +75,7 @@
 
 define float @fmul_poison_op0(float %x) {
 ; CHECK-LABEL: @fmul_poison_op0(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fmul float poison, %x
   ret float %r
@@ -93,7 +91,7 @@
 
 define float @fmul_poison_op1(float %x) {
 ; CHECK-LABEL: @fmul_poison_op1(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fmul float %x, poison
   ret float %r
@@ -109,7 +107,7 @@
 
 define float @fdiv_poison_op0(float %x) {
 ; CHECK-LABEL: @fdiv_poison_op0(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fdiv float poison, %x
   ret float %r
@@ -125,7 +123,7 @@
 
 define float @fdiv_poison_op1(float %x) {
 ; CHECK-LABEL: @fdiv_poison_op1(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = fdiv float %x, poison
   ret float %r
@@ -141,7 +139,7 @@
 
 define float @frem_poison_op0(float %x) {
 ; CHECK-LABEL: @frem_poison_op0(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = frem float poison, %x
   ret float %r
@@ -157,7 +155,7 @@
 
 define float @frem_poison_op1(float %x) {
 ; CHECK-LABEL: @frem_poison_op1(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float poison
 ;
   %r = frem float %x, poison
   ret float %r