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llvm-mirror/test/Transforms/LoopUnroll/partial-unroll-dead-instructions.ll
Justin Bogner 626b423640 [LoopUnroll] Avoid UB when converting from WeakVH to Value *
Calling `operator*` on a WeakVH with a null value yields a null
reference, which is UB. Avoid this by implicitly converting the WeakVH
to a `Value *` rather than dereferencing and then taking the address
for the type conversion.

Differential Revision: https://reviews.llvm.org/D73280
2020-01-23 10:36:39 -08:00

43 lines
1.1 KiB
LLVM

; RUN: opt -S < %s -loop-unroll -unroll-allow-partial=1 | FileCheck %s
;
; Bugpointed test that triggered UB while cleaning up dead
; instructions after simplifying indvars
; We just check that some unrolling happened here - the assert we've
; added to ValueHandleBase::operator* would fire if the bug was still
; present.
; CHECK: atomicrmw volatile add i32*
; CHECK: atomicrmw volatile add i32*
; CHECK: atomicrmw volatile add i32*
@global = external global i32, align 4
define void @widget() {
bb:
br label %bb1
bb1:
br label %bb2
bb2:
%tmp = phi i32 [ 0, %bb1 ], [ %tmp34, %bb33 ]
%tmp3 = phi i32 [ 0, %bb1 ], [ %tmp34, %bb33 ]
%tmp26 = and i32 %tmp, 1073741823
%tmp27 = getelementptr inbounds i32, i32* @global, i32 %tmp26
%tmp28 = atomicrmw volatile add i32* %tmp27, i32 1 monotonic
%tmp29 = icmp ugt i32 %tmp28, 23
%tmp30 = shl i32 %tmp, 6
%tmp31 = add i32 %tmp30, undef
%tmp32 = add i32 %tmp31, %tmp28
store i32 undef, i32* undef, align 4
br label %bb33
bb33:
%tmp34 = add nuw nsw i32 %tmp3, 1
%tmp35 = icmp ult i32 %tmp3, 15
br i1 %tmp35, label %bb2, label %bb36
bb36:
br label %bb1
}