Fix PR14034, an infloop / heap corruption / crash bug in the new SROA.

Thanks to Benjamin for the raw test case. This one took about 50 times
longer to reduce than to fix. =/

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165476 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2012-10-09 01:58:35 +00:00
parent 03753aa759
commit 2fdb25b5a9
2 changed files with 22 additions and 0 deletions

View File

@ -1786,6 +1786,8 @@ static Value *getNaturalGEPWithType(IRBuilder<> &IRB, const DataLayout &TD,
ElementTy = SeqTy->getElementType();
Indices.push_back(IRB.getInt(APInt(TD.getPointerSizeInBits(), 0)));
} else if (StructType *STy = dyn_cast<StructType>(ElementTy)) {
if (STy->element_begin() == STy->element_end())
break; // Nothing left to descend into.
ElementTy = *STy->element_begin();
Indices.push_back(IRB.getInt32(0));
} else {

View File

@ -948,3 +948,23 @@ entry:
ret double %ret
; CHECK: ret double %x
}
%PR14034.struct = type { { {} }, i32, %PR14034.list }
%PR14034.list = type { %PR14034.list*, %PR14034.list* }
define void @PR14034() {
; This test case tries to form GEPs into the empty leading struct members, and
; subsequently crashed (under valgrind) before we fixed the PR. The important
; thing is to handle empty structs gracefully.
; CHECK: @PR14034
entry:
%a = alloca %PR14034.struct
%list = getelementptr %PR14034.struct* %a, i32 0, i32 2
%prev = getelementptr %PR14034.list* %list, i32 0, i32 1
store %PR14034.list* undef, %PR14034.list** %prev
%cast0 = bitcast %PR14034.struct* undef to i8*
%cast1 = bitcast %PR14034.struct* %a to i8*
call void @llvm.memcpy.p0i8.p0i8.i32(i8* %cast0, i8* %cast1, i32 12, i32 0, i1 false)
ret void
}