| Issue |
73512
|
| Summary |
Miscompile after changes to MachineCopyPropagation in commit cae46f6210293ba4d3568eb2
|
| Labels |
|
| Assignees |
|
| Reporter |
bjope
|
We started to see miscompiles downstream after the update to MachineCopyPropagation here: https://github.com/llvm/llvm-project/commit/cae46f6210293ba4d3568eb21b935d438934290d
I managed to reduce one failure and convert it into this (just picking AMDGCPU as target to get something with register tuples):
```
# RUN: llc -mtriple=amdgcn-- -mcpu=gfx900 -run-pass machine-cp -o - %s
---
name: test1
body: |
bb.0:
liveins: $sgpr4_sgpr5, $sgpr6_sgpr7
$sgpr2_sgpr3 = COPY $sgpr6_sgpr7
$sgpr0 = COPY $sgpr3
S_NOP 0, implicit-def $sgpr0
$sgpr3 = COPY killed $sgpr5
$sgpr2_sgpr3 = COPY $sgpr6_sgpr7
S_NOP 0, implicit $sgpr2_sgpr3
...
```
Without the changes to MCP:
```
> llc -mtriple=amdgcn-- -mcpu=gfx900 -o - -run-pass machine-cp mcp.mir
$sgpr2_sgpr3 = COPY $sgpr6_sgpr7
S_NOP 0, implicit-def $sgpr0
$sgpr2_sgpr3 = COPY $sgpr6_sgpr7
S_NOP 0, implicit $sgpr2_sgpr3
```
After cae46f6210293ba4d3568e:
```
> llc -mtriple=amdgcn-- -mcpu=gfx900 -o - -run-pass machine-cp mcp.mir
$sgpr2_sgpr3 = COPY $sgpr6_sgpr7
S_NOP 0, implicit-def $sgpr0
$sgpr3 = COPY killed $sgpr5
S_NOP 0, implicit $sgpr2_sgpr3
```
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