Take memset_inline into account in analyzeLoadFromClobberingMemInst

[gchatelet]

Summary

This appeared in https://reviews.llvm.org/D126903#3884061

[courbet]

llvm/lib/Transforms/Utils/VNCoercion.cpp

359

nit: if (const auto* memset_inst = dyn_cast<MemSetInst>(MI)) to avoid the redundant cast below ?

[gchatelet]

• Address comments

[gchatelet]

Thx for the review.

[thieta]

Should we have a test case as well maybe?

llvm/lib/Transforms/Utils/VNCoercion.cpp

int analyzeLoadFromClobberingMemInst(Type *LoadTy, Value *LoadPtr,
   // If the mem operation is a non-constant size, we can't handle it.
   ConstantInt *SizeCst = dyn_cast<ConstantInt>(MI->getLength());
   if (!SizeCst)
     return -1;
   uint64_t MemSizeInBits = SizeCst->getZExtValue() * 8;
 
   // If this is memset, we just need to see if the offset is valid in the size
   // of the memset..
-  if (MI->getIntrinsicID() == Intrinsic::memset) {
+  if (const auto *memset_inst = dyn_cast<MemSetInst>(MI)) {
     if (DL.isNonIntegralPointerType(LoadTy->getScalarType())) {
-      auto *CI = dyn_cast<ConstantInt>(cast<MemSetInst>(MI)->getValue());
+      auto *CI = dyn_cast<ConstantInt>(memset_inst->getValue());
       if (!CI || !CI->isZero())
         return -1;
     }
     return analyzeLoadFromClobberingWrite(LoadTy, LoadPtr, MI->getDest(),
                                           MemSizeInBits, DL);
   }
 
   // If we have a memcpy/memmove, the only case we can handle is if this is a