SimplifyLibCalls: Simplify fp immediate checking code (NFC)

Re-use already queried call arguments and matched APFloat, instead
of re-matching the original argument.

Author: arsenm

llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

@@ -2082,15 +2082,15 @@ Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow, IRBuilderBase &B) {
   // Evaluate special cases related to a constant base.
 
   const APFloat *BaseF;
-  if (!match(Pow->getArgOperand(0), m_APFloat(BaseF)))
+  if (!match(Base, m_APFloat(BaseF)))
     return nullptr;
 
   AttributeList NoAttrs; // Attributes are only meaningful on the original call
 
   const bool UseIntrinsic = Pow->doesNotAccessMemory();
 
   // pow(2.0, itofp(x)) -> ldexp(1.0, x)
-  if ((UseIntrinsic || !Ty->isVectorTy()) && match(Base, m_SpecificFP(2.0)) &&
+  if ((UseIntrinsic || !Ty->isVectorTy()) && BaseF->isExactlyValue(2.0) &&
       (isa<SIToFPInst>(Expo) || isa<UIToFPInst>(Expo)) &&
       (UseIntrinsic ||
        hasFloatFn(M, TLI, Ty, LibFunc_ldexp, LibFunc_ldexpf, LibFunc_ldexpl))) {
@@ -2137,7 +2137,7 @@ Value *LibCallSimplifier::replacePowWithExp(CallInst *Pow, IRBuilderBase &B) {
   }
 
   // pow(10.0, x) -> exp10(x)
-  if (match(Base, m_SpecificFP(10.0)) &&
+  if (BaseF->isExactlyValue(10.0) &&
       hasFloatFn(M, TLI, Ty, LibFunc_exp10, LibFunc_exp10f, LibFunc_exp10l)) {
 
     if (Pow->doesNotAccessMemory()) {