release/18.x: [AMDGPU] Fix GFX12 encoding of s_wait_event export_ready (#89622)

[AZero13]

As well as flipping the sense of the bit, GFX12 moved it from bit 0 to bit 1 in the encoded simm16 operand.

(cherry picked from commit e0a763c)

[llvmbot]

@llvm/pr-subscribers-backend-amdgpu

Author: AtariDreams (AtariDreams)

Changes

As well as flipping the sense of the bit, GFX12 moved it from bit 0 to bit 1 in the encoded simm16 operand.

(cherry picked from commit e0a763c)

---

Full diff: https://github.com/llvm/llvm-project/pull/91034.diff

2 Files Affected:

• (modified) llvm/lib/Target/AMDGPU/SOPInstructions.td (+1-1)
• (modified) llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.wait.event.ll (+3-7)

diff --git a/llvm/lib/Target/AMDGPU/SOPInstructions.td b/llvm/lib/Target/AMDGPU/SOPInstructions.td
index ae5ef0541929b..5762efde73f02 100644
--- a/llvm/lib/Target/AMDGPU/SOPInstructions.td
+++ b/llvm/lib/Target/AMDGPU/SOPInstructions.td
@@ -1786,7 +1786,7 @@ def : GCNPat<
 let SubtargetPredicate = isNotGFX12Plus in
   def : GCNPat <(int_amdgcn_s_wait_event_export_ready), (S_WAIT_EVENT (i16 0))>;
 let SubtargetPredicate = isGFX12Plus in
-  def : GCNPat <(int_amdgcn_s_wait_event_export_ready), (S_WAIT_EVENT (i16 1))>;
+  def : GCNPat <(int_amdgcn_s_wait_event_export_ready), (S_WAIT_EVENT (i16 2))>;
 
 // The first 10 bits of the mode register are the core FP mode on all
 // subtargets.
diff --git a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.wait.event.ll b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.wait.event.ll
index 08c77148f6ae1..433fefa434988 100644
--- a/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.wait.event.ll
+++ b/llvm/test/CodeGen/AMDGPU/llvm.amdgcn.s.wait.event.ll
@@ -5,14 +5,10 @@
 
 ; GCN-LABEL: {{^}}test_wait_event:
 ; GFX11: s_wait_event 0x0
-; GFX12: s_wait_event 0x1
+; GFX12: s_wait_event 0x2
 
-define amdgpu_ps void @test_wait_event() #0 {
+define amdgpu_ps void @test_wait_event() {
 entry:
-  call void @llvm.amdgcn.s.wait.event.export.ready() #0
+  call void @llvm.amdgcn.s.wait.event.export.ready()
   ret void
 }
-
-declare void @llvm.amdgcn.s.wait.event.export.ready() #0
-
-attributes #0 = { nounwind }

[tstellar]

@AtariDreams (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.

[AZero13]

@AtariDreams (or anyone else). If you would like to add a note about this fix in the release notes (completely optional). Please reply to this comment with a one or two sentence description of the fix. When you are done, please add the release:note label to this PR.

Yes: Fixed encoding of AMDGPU instructions

Also I cannot add labels I do not have that authority

[jayfoad]

Fixed encoding of AMDGPU instructions

I don't think the release notes should say that. It makes it sound like all encodings were wrong.