[ValueTracking] peek through fpext in isKnownNeverInfinity()

https://alive2.llvm.org/ce/z/BkNoRW

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index ddc96f7..4d63194 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -3801,6 +3801,10 @@ bool llvm::isKnownNeverInfinity(const Value *V, const TargetLibraryInfo *TLI,
       Type *FPTy = Inst->getType()->getScalarType();
       return ilogb(APFloat::getLargest(FPTy->getFltSemantics())) >= IntSize;
     }
+    case Instruction::FPExt: {
+      // Peek through to source op. If it is not infinity, this is not infinity.
+      return isKnownNeverInfinity(Inst->getOperand(0), TLI, Depth + 1);
+    }
     default:
       break;
     }