[llvm] r345728 - [InstSimplify] fold 'fcmp nnan ult X, 0.0' when X is not negative

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Wed Oct 31 08:35:46 2018
New Revision: 345728

URL: http://llvm.org/viewvc/llvm-project?rev=345728&view=rev
Log:
[InstSimplify] fold 'fcmp nnan ult X, 0.0' when X is not negative

This is the inverted case for the transform added with D53874 / rL345725.

Modified:
    llvm/trunk/lib/Analysis/InstructionSimplify.cpp
    llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll

Modified: llvm/trunk/lib/Analysis/InstructionSimplify.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InstructionSimplify.cpp?rev=345728&r1=345727&r2=345728&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InstructionSimplify.cpp (original)
+++ llvm/trunk/lib/Analysis/InstructionSimplify.cpp Wed Oct 31 08:35:46 2018
@@ -3620,8 +3620,11 @@ static Value *SimplifyFCmpInst(unsigned
         if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
           return getTrue(RetTy);
         break;
+      case FCmpInst::FCMP_ULT:
+        if (FMF.noNaNs() && CannotBeOrderedLessThanZero(LHS, Q.TLI))
+          return getFalse(RetTy);
+        break;
       case FCmpInst::FCMP_OLT:
-        // X < 0
         if (CannotBeOrderedLessThanZero(LHS, Q.TLI))
           return getFalse(RetTy);
         break;

Modified: llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll?rev=345728&r1=345727&r2=345728&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/floating-point-compare.ll Wed Oct 31 08:35:46 2018
@@ -290,9 +290,7 @@ define <2 x i1> @UIToFP_is_not_negative_
 
 define i1 @UIToFP_nnan_is_not_negative(i32 %x) {
 ; CHECK-LABEL: @UIToFP_nnan_is_not_negative(
-; CHECK-NEXT:    [[A:%.*]] = uitofp i32 [[X:%.*]] to float
-; CHECK-NEXT:    [[R:%.*]] = fcmp nnan ult float [[A]], 0.000000e+00
-; CHECK-NEXT:    ret i1 [[R]]
+; CHECK-NEXT:    ret i1 false
 ;
   %a = uitofp i32 %x to float
   %r = fcmp nnan ult float %a, 0.000000e+00
@@ -301,9 +299,7 @@ define i1 @UIToFP_nnan_is_not_negative(i
 
 define <2 x i1> @UIToFP_nnan_is_not_negative_vec(<2 x i32> %x) {
 ; CHECK-LABEL: @UIToFP_nnan_is_not_negative_vec(
-; CHECK-NEXT:    [[A:%.*]] = uitofp <2 x i32> [[X:%.*]] to <2 x float>
-; CHECK-NEXT:    [[R:%.*]] = fcmp nnan ult <2 x float> [[A]], zeroinitializer
-; CHECK-NEXT:    ret <2 x i1> [[R]]
+; CHECK-NEXT:    ret <2 x i1> zeroinitializer
 ;
   %a = uitofp <2 x i32> %x to <2 x float>
   %r = fcmp nnan ult <2 x float> %a, zeroinitializer
@@ -366,9 +362,7 @@ define <2 x i1> @fabs_is_not_negative_ve
 
 define i1 @fabs_nnan_is_not_negative(double %x) {
 ; CHECK-LABEL: @fabs_nnan_is_not_negative(
-; CHECK-NEXT:    [[FABS:%.*]] = tail call double @llvm.fabs.f64(double [[X:%.*]])
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp nnan ult double [[FABS]], 0.000000e+00
-; CHECK-NEXT:    ret i1 [[CMP]]
+; CHECK-NEXT:    ret i1 false
 ;
   %fabs = tail call double @llvm.fabs.f64(double %x)
   %cmp = fcmp nnan ult double %fabs, 0.0
@@ -377,9 +371,7 @@ define i1 @fabs_nnan_is_not_negative(dou
 
 define <2 x i1> @fabs_nnan_is_not_negative_vec(<2 x double> %x) {
 ; CHECK-LABEL: @fabs_nnan_is_not_negative_vec(
-; CHECK-NEXT:    [[FABS:%.*]] = tail call <2 x double> @llvm.fabs.v2f64(<2 x double> [[X:%.*]])
-; CHECK-NEXT:    [[CMP:%.*]] = fcmp nnan ult <2 x double> [[FABS]], zeroinitializer
-; CHECK-NEXT:    ret <2 x i1> [[CMP]]
+; CHECK-NEXT:    ret <2 x i1> zeroinitializer
 ;
   %fabs = tail call <2 x double> @llvm.fabs.v2f64(<2 x double> %x)
   %cmp = fcmp nnan ult <2 x double> %fabs, zeroinitializer