Merging r169084: into 3.2 release branch.

SROA: Avoid struct and array types early to avoid creating an overly large integer type.

Fixes PR14465.

Differential Revision: http://llvm-reviews.chandlerc.com/D148


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_32@169290 91177308-0d34-0410-b5e6-96231b3b80d8

Author: 32bitmicro

lib/Transforms/Scalar/SROA.cpp

@@ -2160,6 +2160,9 @@ static bool isIntegerWideningViable(const DataLayout &TD,
                                     AllocaPartitioning::const_use_iterator I,
                                     AllocaPartitioning::const_use_iterator E) {
   uint64_t SizeInBits = TD.getTypeSizeInBits(AllocaTy);
+  // Don't create integer types larger than the maximum bitwidth.
+  if (SizeInBits > IntegerType::MAX_INT_BITS)
+    return false;
 
   // Don't try to handle allocas with bit-padding.
   if (SizeInBits != TD.getTypeStoreSizeInBits(AllocaTy))

test/Transforms/SROA/basictest.ll

@@ -1134,3 +1134,16 @@ entry:
   ret void
 ; CHECK: ret
 }
+
+define void @PR14465() {
+; Ensure that we don't crash when analyzing a alloca larger than the maximum
+; integer type width (MAX_INT_BITS) supported by llvm (1048576*32 > (1<<23)-1).
+; CHECK: @PR14465
+
+  %stack = alloca [1048576 x i32], align 16
+; CHECK: alloca [1048576 x i32]
+  %cast = bitcast [1048576 x i32]* %stack to i8*
+  call void @llvm.memset.p0i8.i64(i8* %cast, i8 -2, i64 4194304, i32 16, i1 false)
+  ret void
+; CHECK: ret
+}