[llvm] f898161 - [AMDGPU] Fix image_msaa_load waitcnt insertion for pre-gfx12 (#90710)

[via llvm-commits]

Author: David Stuttard
Date: 2024-05-01T11:37:57+01:00
New Revision: f898161bfa95723954a273a519180e070a5ccd2e

URL: https://github.com/llvm/llvm-project/commit/f898161bfa95723954a273a519180e070a5ccd2e
DIFF: https://github.com/llvm/llvm-project/commit/f898161bfa95723954a273a519180e070a5ccd2e.diff

LOG: [AMDGPU] Fix image_msaa_load waitcnt insertion for pre-gfx12 (#90710)

https://github.com/llvm/llvm-project/pull/90201 made some fixes for
gfx12
image_msaa_load waitcnt insertion.
That fix might break in some situations for pre-gfx12 - this fixes that
by
explitly checking for VSAMPLE which always requires a s_wait_samplecnt
and
leaves the previous logic intact for non-gfx12.

Added: 
    llvm/test/CodeGen/AMDGPU/waitcnt-sample-waw.mir

Modified: 
    llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp b/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
index 6a79ed0a874568..839ac927a0ee41 100644
--- a/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
+++ b/llvm/lib/Target/AMDGPU/SIInsertWaitcnts.cpp
@@ -187,12 +187,12 @@ VmemType getVmemType(const MachineInstr &Inst) {
   const AMDGPU::MIMGInfo *Info = AMDGPU::getMIMGInfo(Inst.getOpcode());
   const AMDGPU::MIMGBaseOpcodeInfo *BaseInfo =
       AMDGPU::getMIMGBaseOpcodeInfo(Info->BaseOpcode);
-  // The test for MSAA here is because gfx12+ image_msaa_load is actually
-  // encoded as VSAMPLE and requires the appropriate s_waitcnt variant for that.
-  // Pre-gfx12 doesn't care since all vmem types result in the same s_waitcnt.
-  return BaseInfo->BVH                         ? VMEM_BVH
-         : BaseInfo->Sampler || BaseInfo->MSAA ? VMEM_SAMPLER
-                                               : VMEM_NOSAMPLER;
+  // We have to make an additional check for isVSAMPLE here since some
+  // instructions don't have a sampler, but are still classified as sampler
+  // instructions for the purposes of e.g. waitcnt.
+  return BaseInfo->BVH                                         ? VMEM_BVH
+         : (BaseInfo->Sampler || SIInstrInfo::isVSAMPLE(Inst)) ? VMEM_SAMPLER
+                                                               : VMEM_NOSAMPLER;
 }
 
 unsigned &getCounterRef(AMDGPU::Waitcnt &Wait, InstCounterType T) {

diff  --git a/llvm/test/CodeGen/AMDGPU/waitcnt-sample-waw.mir b/llvm/test/CodeGen/AMDGPU/waitcnt-sample-waw.mir
new file mode 100644
index 00000000000000..8eb4be266dd3bd
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/waitcnt-sample-waw.mir
@@ -0,0 +1,24 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1100 -verify-machineinstrs -run-pass si-insert-waitcnts -o - %s | FileCheck -check-prefix=GFX11 %s
+
+---
+name:            sample_load_msaa
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $sgpr0, $sgpr1, $sgpr2, $sgpr3, $sgpr4, $sgpr5, $sgpr6, $sgpr7, $sgpr8, $sgpr9, $sgpr10, $sgpr11, $vgpr0, $vgpr1, $vgpr2, $vgpr3, $vgpr4
+
+    ; GFX11-LABEL: name: sample_load_msaa
+    ; GFX11: liveins: $sgpr0, $sgpr1, $sgpr2, $sgpr3, $sgpr4, $sgpr5, $sgpr6, $sgpr7, $sgpr8, $sgpr9, $sgpr10, $sgpr11, $vgpr0, $vgpr1, $vgpr2, $vgpr3, $vgpr4
+    ; GFX11-NEXT: {{  $}}
+    ; GFX11-NEXT: S_WAITCNT 0
+    ; GFX11-NEXT: renamable $vgpr0_vgpr1_vgpr2_vgpr3 = IMAGE_SAMPLE_V4_V1_gfx11 killed renamable $vgpr0, renamable $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7, killed renamable $sgpr8_sgpr9_sgpr10_sgpr11, 15, 0, 0, 0, 0, 0, 0, 0, 0, implicit $exec :: (dereferenceable load (s128), addrspace 8)
+    ; GFX11-NEXT: S_WAITCNT 1015
+    ; GFX11-NEXT: renamable $vgpr0_vgpr1_vgpr2_vgpr3 = IMAGE_MSAA_LOAD_V4_V2_gfx11 killed renamable $vgpr4_vgpr5, killed renamable $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7, 4, 7, -1, 0, 0, -1, 0, 0, 0, implicit $exec :: (dereferenceable load (s128), addrspace 8)
+    ; GFX11-NEXT: S_WAITCNT 1015
+    ; GFX11-NEXT: SI_RETURN_TO_EPILOG killed $vgpr0, killed $vgpr1, killed $vgpr2, killed $vgpr3
+    renamable $vgpr0_vgpr1_vgpr2_vgpr3 = IMAGE_SAMPLE_V4_V1_gfx11 killed renamable $vgpr0, renamable $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7, killed renamable $sgpr8_sgpr9_sgpr10_sgpr11, 15, 0, 0, 0, 0, 0, 0, 0, 0, implicit $exec :: (dereferenceable load (s128), addrspace 8)
+    renamable $vgpr0_vgpr1_vgpr2_vgpr3 = IMAGE_MSAA_LOAD_V4_V2_gfx11 killed renamable $vgpr4_vgpr5, killed renamable $sgpr0_sgpr1_sgpr2_sgpr3_sgpr4_sgpr5_sgpr6_sgpr7, 4, 7, -1, 0, 0, -1, 0, 0, 0, implicit $exec :: (dereferenceable load (s128), addrspace 8)
+    SI_RETURN_TO_EPILOG killed $vgpr0, killed $vgpr1, killed $vgpr2, killed $vgpr3
+
+...