| Issue |
52950
|
| Summary |
LoadStoreVectorizer assumes non-willreturn calls return
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
nunoplopes
|
Test: Transforms/LoadStoreVectorizer/int_sideeffect.ll
The transformation below is incorrect if `%p` points to just 12-bytes of dereferenceable memory and `@foo` exits.
```
define void @test_inaccessiblememonly(* %p) {
%p0 = gep * %p, 4 x i64 0
%p1 = gep * %p, 4 x i64 1
%p2 = gep * %p, 4 x i64 2
%p3 = gep * %p, 4 x i64 3
%l0 = load float, * %p0, align 16
%l1 = load float, * %p1, align 4
%l2 = load float, * %p2, align 4
call void @foo() inaccessiblememonly
%l3 = load float, * %p3, align 4
store float %l0, * %p0, align 16
call void @foo() inaccessiblememonly
store float %l1, * %p1, align 4
store float %l2, * %p2, align 4
store float %l3, * %p3, align 4
ret void
}
=>
define void @test_inaccessiblememonly(* %p) {
%p0 = gep * %p, 4 x i64 0
%1 = bitcast * %p0 to *
%2 = load <4 x float>, * %1, align 16
%l01 = extractelement <4 x float> %2, i32 0
%l12 = extractelement <4 x float> %2, i32 1
%l23 = extractelement <4 x float> %2, i32 2
%l34 = extractelement <4 x float> %2, i32 3
call void @foo() inaccessiblememonly
call void @foo() inaccessiblememonly
%3 = insertelement <4 x float> poison, float %l01, i32 0
%4 = insertelement <4 x float> %3, float %l12, i32 1
%5 = insertelement <4 x float> %4, float %l23, i32 2
%6 = insertelement <4 x float> %5, float %l34, i32 3
%7 = bitcast * %p0 to *
store <4 x float> %6, * %7, align 16
ret void
}
Transformation doesn't verify!
ERROR: Source is more defined than target
Example:
* %p = pointer(non-local, block_id=1, offset=0)
Source:
* %p0 = pointer(non-local, block_id=1, offset=0)
* %p1 = pointer(non-local, block_id=1, offset=4)
* %p2 = pointer(non-local, block_id=1, offset=8)
* %p3 = pointer(non-local, block_id=1, offset=12)
float %l0 = poison
float %l1 = poison
float %l2 = poison
void = UB triggered!
SOURCE MEMORY STATE
===================
NON-LOCAL BLOCKS:
Block 0 > size: 0 align: 1 alloc type: 0
Block 1 > size: 12 align: 32 alloc type: 0
Block 2 > align: 4 alloc type: 0
Target:
* %p0 = pointer(non-local, block_id=1, offset=0)
* %1 = pointer(non-local, block_id=1, offset=0)
<4 x float> %2 = UB triggered!
```
cc @nikic
https://github.com/llvm/llvm-project/commit/9d720dcb89e8da4d12aa1832d74614adc6aa2c82
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