[llvm] r346242 - [InstCombine] propagate fast-math-flags when folding fcmp+fpext, part 2

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Tue Nov  6 08:45:27 2018
New Revision: 346242

URL: http://llvm.org/viewvc/llvm-project?rev=346242&view=rev
Log:
[InstCombine] propagate fast-math-flags when folding fcmp+fpext, part 2

Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
    llvm/trunk/test/Transforms/InstCombine/fcmp.ll

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=346242&r1=346241&r2=346242&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue Nov  6 08:45:27 2018
@@ -5483,9 +5483,12 @@ Instruction *InstCombiner::visitFCmpInst
       Fabs.clearSign();
       if (!Lossy &&
           ((Fabs.compare(APFloat::getSmallestNormalized(FPSem)) !=
-            APFloat::cmpLessThan) || Fabs.isZero()))
-        // TODO: Propagate FMF.
-        return new FCmpInst(Pred, X, ConstantFP::get(C->getContext(), F));
+            APFloat::cmpLessThan) || Fabs.isZero())) {
+        Instruction *NewFCmp =
+            new FCmpInst(Pred, X, ConstantFP::get(C->getContext(), F));
+        NewFCmp->copyFastMathFlags(&I);
+        return NewFCmp;
+      }
     }
   }
 

Modified: llvm/trunk/test/Transforms/InstCombine/fcmp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fcmp.ll?rev=346242&r1=346241&r2=346242&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fcmp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fcmp.ll Tue Nov  6 08:45:27 2018
@@ -18,7 +18,7 @@ define i1 @test1(float %x, float %y) {
 
 define i1 @test2(float %a) {
 ; CHECK-LABEL: @test2(
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp ogt float [[A:%.*]], 1.000000e+00
+; CHECK-NEXT:    [[CMP:%.*]] = fcmp ninf ogt float [[A:%.*]], 1.000000e+00
 ; CHECK-NEXT:    ret i1 [[CMP]]
 ;
   %ext = fpext float %a to double