[llvm] 78056e2 - [InstCombine] propagate FMF in exp2->ldexp fold

[Sanjay Patel via llvm-commits]

Author: Sanjay Patel
Date: 2023-02-10T10:02:25-05:00
New Revision: 78056e2f2d9510d2ace42fe7e9eb60e5abe8a3e7

URL: https://github.com/llvm/llvm-project/commit/78056e2f2d9510d2ace42fe7e9eb60e5abe8a3e7
DIFF: https://github.com/llvm/llvm-project/commit/78056e2f2d9510d2ace42fe7e9eb60e5abe8a3e7.diff

LOG: [InstCombine] propagate FMF in exp2->ldexp fold

Added: 
    

Modified: 
    llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
    llvm/test/Transforms/InstCombine/exp2-1.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index a1ed93622f73..746f61f4796a 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -2226,15 +2226,17 @@ Value *LibCallSimplifier::optimizeExp2(CallInst *CI, IRBuilderBase &B) {
 
   // exp2(sitofp(x)) -> ldexp(1.0, sext(x))  if sizeof(x) <= IntSize
   // exp2(uitofp(x)) -> ldexp(1.0, zext(x))  if sizeof(x) < IntSize
-  // TODO: This does not propagate FMF.
   Value *Op = CI->getArgOperand(0);
   if ((isa<SIToFPInst>(Op) || isa<UIToFPInst>(Op)) &&
       hasFloatFn(M, TLI, Ty, LibFunc_ldexp, LibFunc_ldexpf, LibFunc_ldexpl)) {
-    if (Value *Exp = getIntToFPVal(Op, B, TLI->getIntSize()))
+    if (Value *Exp = getIntToFPVal(Op, B, TLI->getIntSize())) {
+      IRBuilderBase::FastMathFlagGuard Guard(B);
+      B.setFastMathFlags(CI->getFastMathFlags());
       return copyFlags(
           *CI, emitBinaryFloatFnCall(ConstantFP::get(Ty, 1.0), Exp, TLI,
                                      LibFunc_ldexp, LibFunc_ldexpf,
                                      LibFunc_ldexpl, B, AttributeList()));
+    }
   }
 
   return Ret;

diff  --git a/llvm/test/Transforms/InstCombine/exp2-1.ll b/llvm/test/Transforms/InstCombine/exp2-1.ll
index c441073a4025..79aeded2fa5c 100644
--- a/llvm/test/Transforms/InstCombine/exp2-1.ll
+++ b/llvm/test/Transforms/InstCombine/exp2-1.ll
@@ -275,17 +275,15 @@ define float @test_simplify10(i8 zeroext %x) {
   ret float %ret
 }
 
-; TODO: FMF could be propagated when transforming.
-
 define float @sitofp_scalar_intrinsic_with_FMF(i8 %x) {
 ; LDEXP32-LABEL: @sitofp_scalar_intrinsic_with_FMF(
 ; LDEXP32-NEXT:    [[TMP1:%.*]] = sext i8 [[X:%.*]] to i32
-; LDEXP32-NEXT:    [[LDEXPF:%.*]] = tail call float @ldexpf(float 1.000000e+00, i32 [[TMP1]])
+; LDEXP32-NEXT:    [[LDEXPF:%.*]] = tail call nnan float @ldexpf(float 1.000000e+00, i32 [[TMP1]])
 ; LDEXP32-NEXT:    ret float [[LDEXPF]]
 ;
 ; LDEXP16-LABEL: @sitofp_scalar_intrinsic_with_FMF(
 ; LDEXP16-NEXT:    [[TMP1:%.*]] = sext i8 [[X:%.*]] to i16
-; LDEXP16-NEXT:    [[LDEXPF:%.*]] = tail call float @ldexpf(float 1.000000e+00, i16 [[TMP1]])
+; LDEXP16-NEXT:    [[LDEXPF:%.*]] = tail call nnan float @ldexpf(float 1.000000e+00, i16 [[TMP1]])
 ; LDEXP16-NEXT:    ret float [[LDEXPF]]
 ;
 ; NOLDEXPF-LABEL: @sitofp_scalar_intrinsic_with_FMF(