From d79ef021fe9afc15bec09c00d30501eae1347d7b Mon Sep 17 00:00:00 2001
From: Sanjay Patel <spatel@rotateright.com>
Date: Tue, 5 Jan 2016 20:46:19 +0000
Subject: [PATCH] [LibCallSimplfier] use instruction-level fast-math-flags for
 fmin/fmax transforms

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@256871 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Utils/SimplifyLibCalls.cpp |  6 ++---
 test/Transforms/InstCombine/fast-math.ll  | 33 +++++++++++------------
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index bf158949de0..5004b74fbae 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -1317,14 +1317,12 @@ Value *LibCallSimplifier::optimizeFMinFMax(CallInst *CI, IRBuilder<> &B) {
 
   IRBuilder<>::FastMathFlagGuard Guard(B);
   FastMathFlags FMF;
-  Function *F = CI->getParent()->getParent();
-  if (canUseUnsafeFPMath(F)) {
+  if (CI->hasUnsafeAlgebra()) {
     // Unsafe algebra sets all fast-math-flags to true.
     FMF.setUnsafeAlgebra();
   } else {
     // At a minimum, no-nans-fp-math must be true.
-    Attribute Attr = F->getFnAttribute("no-nans-fp-math");
-    if (Attr.getValueAsString() != "true")
+    if (!CI->hasNoNaNs())
       return nullptr;
     // No-signed-zeros is implied by the definitions of fmax/fmin themselves:
     // "Ideally, fmax would be sensitive to the sign of zero, for example
diff --git a/test/Transforms/InstCombine/fast-math.ll b/test/Transforms/InstCombine/fast-math.ll
index fd563481b3e..5bdf48b85ce 100644
--- a/test/Transforms/InstCombine/fast-math.ll
+++ b/test/Transforms/InstCombine/fast-math.ll
@@ -733,13 +733,12 @@ declare fp128 @fminl(fp128, fp128)
 ; This should always be set when unsafe-fp-math is true, but
 ; alternate the attributes for additional test coverage.
 ; 'nsz' is implied by the definition of fmax or fmin itself.
-attributes #1 = { "no-nans-fp-math" = "true" }
 
 ; Shrink and remove the call.
-define float @max1(float %a, float %b) #0 {
+define float @max1(float %a, float %b) {
   %c = fpext float %a to double
   %d = fpext float %b to double
-  %e = call double @fmax(double %c, double %d)
+  %e = call fast double @fmax(double %c, double %d)
   %f = fptrunc double %e to float
   ret float %f
 
@@ -749,8 +748,8 @@ define float @max1(float %a, float %b) #0 {
 ; CHECK-NEXT:  ret
 }
 
-define float @max2(float %a, float %b) #1 {
-  %c = call float @fmaxf(float %a, float %b)
+define float @max2(float %a, float %b) {
+  %c = call nnan float @fmaxf(float %a, float %b)
   ret float %c
 
 ; CHECK-LABEL: max2(
@@ -760,8 +759,8 @@ define float @max2(float %a, float %b) #1 {
 }
 
 
-define double @max3(double %a, double %b) #0 {
-  %c = call double @fmax(double %a, double %b)
+define double @max3(double %a, double %b) {
+  %c = call fast double @fmax(double %a, double %b)
   ret double %c
 
 ; CHECK-LABEL: max3(
@@ -770,8 +769,8 @@ define double @max3(double %a, double %b) #0 {
 ; CHECK-NEXT:  ret
 }
 
-define fp128 @max4(fp128 %a, fp128 %b) #1 {
-  %c = call fp128 @fmaxl(fp128 %a, fp128 %b)
+define fp128 @max4(fp128 %a, fp128 %b) {
+  %c = call nnan fp128 @fmaxl(fp128 %a, fp128 %b)
   ret fp128 %c
 
 ; CHECK-LABEL: max4(
@@ -781,10 +780,10 @@ define fp128 @max4(fp128 %a, fp128 %b) #1 {
 }
 
 ; Shrink and remove the call.
-define float @min1(float %a, float %b) #1 {
+define float @min1(float %a, float %b) {
   %c = fpext float %a to double
   %d = fpext float %b to double
-  %e = call double @fmin(double %c, double %d)
+  %e = call nnan double @fmin(double %c, double %d)
   %f = fptrunc double %e to float
   ret float %f
 
@@ -794,8 +793,8 @@ define float @min1(float %a, float %b) #1 {
 ; CHECK-NEXT:  ret
 }
 
-define float @min2(float %a, float %b) #0 {
-  %c = call float @fminf(float %a, float %b)
+define float @min2(float %a, float %b) {
+  %c = call fast float @fminf(float %a, float %b)
   ret float %c
 
 ; CHECK-LABEL: min2(
@@ -804,8 +803,8 @@ define float @min2(float %a, float %b) #0 {
 ; CHECK-NEXT:  ret
 }
 
-define double @min3(double %a, double %b) #1 {
-  %c = call double @fmin(double %a, double %b)
+define double @min3(double %a, double %b) {
+  %c = call nnan double @fmin(double %a, double %b)
   ret double %c
 
 ; CHECK-LABEL: min3(
@@ -814,8 +813,8 @@ define double @min3(double %a, double %b) #1 {
 ; CHECK-NEXT:  ret
 }
 
-define fp128 @min4(fp128 %a, fp128 %b) #0 {
-  %c = call fp128 @fminl(fp128 %a, fp128 %b)
+define fp128 @min4(fp128 %a, fp128 %b) {
+  %c = call fast fp128 @fminl(fp128 %a, fp128 %b)
   ret fp128 %c
 
 ; CHECK-LABEL: min4(
-- 
2.34.1