hoist the check for alloca size up so that it controls CanConvertToScalar

as well as isSafeAllocaToScalarRepl.

llvm-svn: 65755

llvm/lib/Transforms/Scalar/ScalarReplAggregates.cpp

@@ -253,11 +253,13 @@ bool SROA::performScalarRepl(Function &F) {
     // (allocations OF arrays are ok though), and an allocation of a scalar
     // value cannot be decomposed at all.
     uint64_t AllocaSize = TD->getTypePaddedSize(AI->getAllocatedType());
-        
+
+    // Do not promote any struct whose size is too big.
+    if (AllocaSize < SRThreshold)
+      continue;
+    
     if ((isa<StructType>(AI->getAllocatedType()) ||
          isa<ArrayType>(AI->getAllocatedType())) &&
-        // Do not promote any struct whose size is too big.
-        AllocaSize < SRThreshold &&
         // Do not promote any struct into more than "32" separate vars.
         getNumSAElements(AI->getAllocatedType()) < SRThreshold/4) {
       // Check that all of the users of the allocation are capable of being