[llvm] 29e4363 - ValueTracking: Look through fneg in isKnownNeverNaN

[Matt Arsenault via llvm-commits]

Author: Matt Arsenault
Date: 2022-11-17T08:35:49-08:00
New Revision: 29e4363dda1b4d227ebd4d8e86783b05c4543432

URL: https://github.com/llvm/llvm-project/commit/29e4363dda1b4d227ebd4d8e86783b05c4543432
DIFF: https://github.com/llvm/llvm-project/commit/29e4363dda1b4d227ebd4d8e86783b05c4543432.diff

LOG: ValueTracking: Look through fneg in isKnownNeverNaN

Added: 
    

Modified: 
    llvm/lib/Analysis/ValueTracking.cpp
    llvm/test/Transforms/InstSimplify/known-never-nan.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 40e4253fae53..4c73eca580f5 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -3869,6 +3869,7 @@ bool llvm::isKnownNeverNaN(const Value *V, const TargetLibraryInfo *TLI,
       return true;
     case Instruction::FPTrunc:
     case Instruction::FPExt:
+    case Instruction::FNeg:
       return isKnownNeverNaN(Inst->getOperand(0), TLI, Depth + 1);
     default:
       break;

diff  --git a/llvm/test/Transforms/InstSimplify/known-never-nan.ll b/llvm/test/Transforms/InstSimplify/known-never-nan.ll
index 8b24b2798e65..d6a2924a0215 100644
--- a/llvm/test/Transforms/InstSimplify/known-never-nan.ll
+++ b/llvm/test/Transforms/InstSimplify/known-never-nan.ll
@@ -291,9 +291,7 @@ define i1 @nnan_binary_fneg() {
 define i1 @nnan_unary_fneg() {
 ; CHECK-LABEL: @nnan_unary_fneg(
 ; CHECK-NEXT:    [[NNAN:%.*]] = call nnan double @func()
-; CHECK-NEXT:    [[OP:%.*]] = fneg double [[NNAN]]
-; CHECK-NEXT:    [[TMP:%.*]] = fcmp ord double [[OP]], [[OP]]
-; CHECK-NEXT:    ret i1 [[TMP]]
+; CHECK-NEXT:    ret i1 true
 ;
   %nnan = call nnan double @func()
   %op = fneg double %nnan