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AMDGPU: Fix broken negative test from ancient times #131106

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merged 1 commit into from
Mar 13, 2025
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AMDGPU: Fix broken negative test from ancient times #131106

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18 changes: 14 additions & 4 deletions llvm/test/CodeGen/AMDGPU/dead-machine-elim-after-dead-lane.ll
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Original file line number Diff line number Diff line change
@@ -1,12 +1,22 @@
; RUN: llc -mtriple=amdgcn -verify-machineinstrs %s -o - | FileCheck %s
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
; RUN: llc -mtriple=amdgcn -mcpu=tahiti %s -o - | FileCheck %s

; CHECK-LABEL: foo
; CHECK-NOT: BUFFER_LOAD_DWORDX2_OFFSET
; After dead code elimination, that buffer load should be eliminated finally
; after dead lane detection.
define amdgpu_kernel void @foo() {
; CHECK-LABEL: foo:
; CHECK: ; %bb.0: ; %entry
; CHECK-NEXT: s_cbranch_execnz .LBB0_2
; CHECK-NEXT: ; %bb.1: ; %LeafBlock1
; CHECK-NEXT: .LBB0_2: ; %foo.exit
; CHECK-NEXT: s_mov_b32 s3, 0xf000
; CHECK-NEXT: s_mov_b32 s2, -1
; CHECK-NEXT: v_mov_b32_e32 v0, 0
; CHECK-NEXT: buffer_store_dword v0, off, s[0:3], 0
; CHECK-NEXT: s_endpgm
; CHECK-NEXT: ; %bb.3: ; %sw.bb10
entry:
switch i8 undef, label %foo.exit [
switch i8 poison, label %foo.exit [
i8 4, label %sw.bb4
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In one of the prev. PR github actions suggested following:

In tests, avoid using undef and having tests that trigger undefined behavior. If you need an operand with some unimportant value, you can add a new argument to the function and use that instead.

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The bot is very overzealous and has no contextual understanding. This test needs to preserve the codegen output as exactly as possible, regardless of how well defined the program is

i8 10, label %sw.bb10
]
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