[AggressiveInstCombine] Merge consecutive loads of mixed sizes (#129263)

Proof: https://alive2.llvm.org/ce/z/r7M-Sf
Closes: #128134

Author: Cancelll

llvm/lib/Transforms/AggressiveInstCombine/AggressiveInstCombine.cpp

@@ -675,14 +675,15 @@ static bool foldLoadsRecursive(Value *V, LoadOps &LOps, const DataLayout &DL,
       Load2Ptr->stripAndAccumulateConstantOffsets(DL, Offset2,
                                                   /* AllowNonInbounds */ true);
 
-  // Verify if both loads have same base pointers and load sizes are same.
+  // Verify if both loads have same base pointers
   uint64_t LoadSize1 = LI1->getType()->getPrimitiveSizeInBits();
   uint64_t LoadSize2 = LI2->getType()->getPrimitiveSizeInBits();
-  if (Load1Ptr != Load2Ptr || LoadSize1 != LoadSize2)
+  if (Load1Ptr != Load2Ptr)
     return false;
 
-  // Support Loadsizes greater or equal to 8bits and only power of 2.
-  if (LoadSize1 < 8 || !isPowerOf2_64(LoadSize1))
+  // Make sure that there are no padding bits.
+  if (!DL.typeSizeEqualsStoreSize(LI1->getType()) ||
+      !DL.typeSizeEqualsStoreSize(LI2->getType()))
     return false;
 
   // Alias Analysis to check for stores b/w the loads.