From e208d8fad23f01d36cc0ce7bd5f7c61c3c39774d Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Thu, 12 Mar 2020 09:52:06 -0400
Subject: [PATCH] [InstSimplify] simplify FP ops harder with FMF (part 2)

This is part of the IR sibling for:
D75576

Related transform committed with:
rG8ec71585719d
---
 lib/Analysis/InstructionSimplify.cpp     |  6 +++---
 test/Transforms/InstSimplify/fp-undef.ll | 20 ++++++++++----------
 2 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index 6144618003d..de7310623e8 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -4611,11 +4611,11 @@ static Constant *simplifyFPOp(ArrayRef<Value *> Ops,
     bool IsUndef = match(V, m_Undef());
 
     // If this operation has 'nnan' or 'ninf' and at least 1 disallowed operand
-    // (TODO: an undef operand can be chosen to be Nan/Inf), then the result of
+    // (an undef operand can be chosen to be Nan/Inf), then the result of
     // this operation is poison. That result can be relaxed to undef.
-    if (FMF.noNaNs() && IsNan)
+    if (FMF.noNaNs() && (IsNan || IsUndef))
       return UndefValue::get(V->getType());
-    if (FMF.noInfs() && IsInf)
+    if (FMF.noInfs() && (IsInf || IsUndef))
       return UndefValue::get(V->getType());
 
     if (IsUndef || IsNan)
diff --git a/test/Transforms/InstSimplify/fp-undef.ll b/test/Transforms/InstSimplify/fp-undef.ll
index cdf887f3363..7b11955d9b3 100644
--- a/test/Transforms/InstSimplify/fp-undef.ll
+++ b/test/Transforms/InstSimplify/fp-undef.ll
@@ -85,7 +85,7 @@ define float @frem_undef_op1(float %x) {
 
 define float @fadd_undef_op0_nnan(float %x) {
 ; CHECK-LABEL: @fadd_undef_op0_nnan(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fadd nnan float undef, %x
   ret float %r
@@ -93,7 +93,7 @@ define float @fadd_undef_op0_nnan(float %x) {
 
 define float @fadd_undef_op1_fast(float %x) {
 ; CHECK-LABEL: @fadd_undef_op1_fast(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fadd fast float %x, undef
   ret float %r
@@ -101,7 +101,7 @@ define float @fadd_undef_op1_fast(float %x) {
 
 define float @fsub_undef_op0_fast(float %x) {
 ; CHECK-LABEL: @fsub_undef_op0_fast(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fsub fast float undef, %x
   ret float %r
@@ -109,7 +109,7 @@ define float @fsub_undef_op0_fast(float %x) {
 
 define float @fsub_undef_op1_nnan(float %x) {
 ; CHECK-LABEL: @fsub_undef_op1_nnan(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fsub nnan float %x, undef
   ret float %r
@@ -117,7 +117,7 @@ define float @fsub_undef_op1_nnan(float %x) {
 
 define float @fmul_undef_op0_nnan(float %x) {
 ; CHECK-LABEL: @fmul_undef_op0_nnan(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fmul nnan float undef, %x
   ret float %r
@@ -125,7 +125,7 @@ define float @fmul_undef_op0_nnan(float %x) {
 
 define float @fmul_undef_op1_fast(float %x) {
 ; CHECK-LABEL: @fmul_undef_op1_fast(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fmul fast float %x, undef
   ret float %r
@@ -133,7 +133,7 @@ define float @fmul_undef_op1_fast(float %x) {
 
 define float @fdiv_undef_op0_fast(float %x) {
 ; CHECK-LABEL: @fdiv_undef_op0_fast(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fdiv fast float undef, %x
   ret float %r
@@ -141,7 +141,7 @@ define float @fdiv_undef_op0_fast(float %x) {
 
 define float @fdiv_undef_op1_nnan(float %x) {
 ; CHECK-LABEL: @fdiv_undef_op1_nnan(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = fdiv nnan float %x, undef
   ret float %r
@@ -149,7 +149,7 @@ define float @fdiv_undef_op1_nnan(float %x) {
 
 define float @frem_undef_op0_nnan(float %x) {
 ; CHECK-LABEL: @frem_undef_op0_nnan(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = frem nnan float undef, %x
   ret float %r
@@ -157,7 +157,7 @@ define float @frem_undef_op0_nnan(float %x) {
 
 define float @frem_undef_op1_fast(float %x) {
 ; CHECK-LABEL: @frem_undef_op1_fast(
-; CHECK-NEXT:    ret float 0x7FF8000000000000
+; CHECK-NEXT:    ret float undef
 ;
   %r = frem fast float %x, undef
   ret float %r