[InstCombine] intersect FMF when reassociating FP min/max intrinsics

As discussed in PR45478:
https://bugs.llvm.org/show_bug.cgi?id=45478
...propagating FMF from the outer (second) call is not correct,
so intersect them instead.
I suspect we could do better (see TODO comment), but mismatched
FMF is probably too rare to care about.

Differential Revision: https://reviews.llvm.org/D78631

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index bdc4441..765eb24 100644 (file)
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -2298,8 +2298,11 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
           llvm_unreachable("unexpected intrinsic ID");
         }
         Instruction *NewCall = Builder.CreateBinaryIntrinsic(
-            IID, X, ConstantFP::get(Arg0->getType(), Res));
-        NewCall->copyIRFlags(II);
+            IID, X, ConstantFP::get(Arg0->getType(), Res), II);
+        // TODO: Conservatively intersecting FMF. If Res == C2, the transform
+        //       was a simplification (so Arg0 and its original flags could
+        //       propagate?)
+        NewCall->andIRFlags(M);
         return replaceInstUsesWith(*II, NewCall);
       }
     }

diff --git a/llvm/test/Transforms/InstCombine/maximum.ll b/llvm/test/Transforms/InstCombine/maximum.ll
index 770f42e..1a0dfa1 100644 (file)
--- a/llvm/test/Transforms/InstCombine/maximum.ll
+++ b/llvm/test/Transforms/InstCombine/maximum.ll
@@ -157,7 +157,7 @@ define float @maximum_f32_1_maximum_val_p0(float %x) {
 
 define float @maximum_f32_1_maximum_p0_val_fast(float %x) {
 ; CHECK-LABEL: @maximum_f32_1_maximum_p0_val_fast(
-; CHECK-NEXT:    [[TMP1:%.*]] = call fast float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call float @llvm.maximum.f32(float 0.0, float %x)
@@ -167,7 +167,7 @@ define float @maximum_f32_1_maximum_p0_val_fast(float %x) {
 
 define float @maximum_f32_1_maximum_p0_val_fmf1(float %x) {
 ; CHECK-LABEL: @maximum_f32_1_maximum_p0_val_fmf1(
-; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf arcp float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call nnan arcp float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call arcp nnan float @llvm.maximum.f32(float 0.0, float %x)
@@ -187,7 +187,7 @@ define float @maximum_f32_1_maximum_p0_val_fmf2(float %x) {
 
 define float @maximum_f32_1_maximum_p0_val_fmf3(float %x) {
 ; CHECK-LABEL: @maximum_f32_1_maximum_p0_val_fmf3(
-; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf arcp float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf float @llvm.maximum.f32(float [[X:%.*]], float 1.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call nnan ninf float @llvm.maximum.f32(float 0.0, float %x)

diff --git a/llvm/test/Transforms/InstCombine/maxnum.ll b/llvm/test/Transforms/InstCombine/maxnum.ll
index f68651a..71ce436 100644 (file)
--- a/llvm/test/Transforms/InstCombine/maxnum.ll
+++ b/llvm/test/Transforms/InstCombine/maxnum.ll
@@ -157,7 +157,7 @@ define float @maxnum_f32_1_maxnum_val_p0(float %x) {
 
 define float @maxnum_f32_1_maxnum_p0_val_fast(float %x) {
 ; CHECK-LABEL: @maxnum_f32_1_maxnum_p0_val_fast(
-; CHECK-NEXT:    [[TMP1:%.*]] = call fast float @llvm.maxnum.f32(float [[X:%.*]], float 1.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.maxnum.f32(float [[X:%.*]], float 1.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call float @llvm.maxnum.f32(float 0.0, float %x)
@@ -167,7 +167,7 @@ define float @maxnum_f32_1_maxnum_p0_val_fast(float %x) {
 
 define float @minnum_f32_1_maxnum_p0_val_fmf1(float %x) {
 ; CHECK-LABEL: @minnum_f32_1_maxnum_p0_val_fmf1(
-; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf float @llvm.maxnum.f32(float [[X:%.*]], float 1.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call nnan float @llvm.maxnum.f32(float [[X:%.*]], float 1.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call nnan float @llvm.maxnum.f32(float 0.0, float %x)

diff --git a/llvm/test/Transforms/InstCombine/minimum.ll b/llvm/test/Transforms/InstCombine/minimum.ll
index 39bf5e7..cc2fe28 100644 (file)
--- a/llvm/test/Transforms/InstCombine/minimum.ll
+++ b/llvm/test/Transforms/InstCombine/minimum.ll
@@ -159,7 +159,7 @@ define float @minimum_f32_1_minimum_val_p0(float %x) {
 
 define float @minimum_f32_1_minimum_p0_val_fast(float %x) {
 ; CHECK-LABEL: @minimum_f32_1_minimum_p0_val_fast(
-; CHECK-NEXT:    [[TMP1:%.*]] = call fast float @llvm.minimum.f32(float [[X:%.*]], float 0.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.minimum.f32(float [[X:%.*]], float 0.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call float @llvm.minimum.f32(float 0.0, float %x)
@@ -169,7 +169,7 @@ define float @minimum_f32_1_minimum_p0_val_fast(float %x) {
 
 define float @minimum_f32_1_minimum_p0_val_fmf1(float %x) {
 ; CHECK-LABEL: @minimum_f32_1_minimum_p0_val_fmf1(
-; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf float @llvm.minimum.f32(float [[X:%.*]], float 0.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.minimum.f32(float [[X:%.*]], float 0.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call float @llvm.minimum.f32(float 0.0, float %x)

diff --git a/llvm/test/Transforms/InstCombine/minnum.ll b/llvm/test/Transforms/InstCombine/minnum.ll
index bd078a2..007c4aa 100644 (file)
--- a/llvm/test/Transforms/InstCombine/minnum.ll
+++ b/llvm/test/Transforms/InstCombine/minnum.ll
@@ -159,7 +159,7 @@ define float @minnum_f32_1_minnum_val_p0(float %x) {
 
 define float @minnum_f32_1_minnum_p0_val_fast(float %x) {
 ; CHECK-LABEL: @minnum_f32_1_minnum_p0_val_fast(
-; CHECK-NEXT:    [[TMP1:%.*]] = call fast float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call float @llvm.minnum.f32(float 0.0, float %x)
@@ -169,7 +169,7 @@ define float @minnum_f32_1_minnum_p0_val_fast(float %x) {
 
 define float @minnum_f32_1_minnum_p0_val_fmf1(float %x) {
 ; CHECK-LABEL: @minnum_f32_1_minnum_p0_val_fmf1(
-; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call nnan float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call nsz nnan float @llvm.minnum.f32(float 0.0, float %x)
@@ -179,7 +179,7 @@ define float @minnum_f32_1_minnum_p0_val_fmf1(float %x) {
 
 define float @minnum_f32_1_minnum_p0_val_fmf2(float %x) {
 ; CHECK-LABEL: @minnum_f32_1_minnum_p0_val_fmf2(
-; CHECK-NEXT:    [[TMP1:%.*]] = call ninf nsz float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
+; CHECK-NEXT:    [[TMP1:%.*]] = call ninf float @llvm.minnum.f32(float [[X:%.*]], float 0.000000e+00)
 ; CHECK-NEXT:    ret float [[TMP1]]
 ;
   %y = call nnan ninf float @llvm.minnum.f32(float 0.0, float %x)