[llvm] 5c974d0 - [AMDGPU] Fix hazard handling of v_cmpx to permlane

[Stanislav Mekhanoshin via llvm-commits]

Author: Stanislav Mekhanoshin
Date: 2022-06-09T10:33:54-07:00
New Revision: 5c974d086c22d519e3e649f1d5fe213b03d6ba25

URL: https://github.com/llvm/llvm-project/commit/5c974d086c22d519e3e649f1d5fe213b03d6ba25
DIFF: https://github.com/llvm/llvm-project/commit/5c974d086c22d519e3e649f1d5fe213b03d6ba25.diff

LOG: [AMDGPU] Fix hazard handling of v_cmpx to permlane

- VOP3 and SDWA forms of V_CMPX were not handled
- Hazard only exists if the compare defines EXEC (i.e. V_CMPX)
  forwarded to the permlane.

Differential Revision: https://reviews.llvm.org/D127344

Added: 
    llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard-sdwa.mir

Modified: 
    llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
    llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard.mir

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
index 51d3704d5645..099f4faf0b89 100644
--- a/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
+++ b/llvm/lib/Target/AMDGPU/GCNHazardRecognizer.cpp
@@ -1038,7 +1038,12 @@ bool GCNHazardRecognizer::fixVcmpxPermlaneHazards(MachineInstr *MI) {
     return false;
 
   const SIInstrInfo *TII = ST.getInstrInfo();
-  auto IsHazardFn = [TII](const MachineInstr &MI) { return TII->isVOPC(MI); };
+  const SIRegisterInfo *TRI = ST.getRegisterInfo();
+  auto IsHazardFn = [TII, TRI](const MachineInstr &MI) {
+    return (TII->isVOPC(MI) ||
+            ((TII->isVOP3(MI) || TII->isSDWA(MI)) && MI.isCompare())) &&
+           MI.modifiesRegister(AMDGPU::EXEC, TRI);
+  };
 
   auto IsExpiredFn = [](const MachineInstr &MI, int) {
     unsigned Opc = MI.getOpcode();

diff  --git a/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard-sdwa.mir b/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard-sdwa.mir
new file mode 100644
index 000000000000..197232da66a4
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard-sdwa.mir
@@ -0,0 +1,24 @@
+# RUN: llc -march=amdgcn -mcpu=gfx1010 -verify-machineinstrs -run-pass post-RA-hazard-rec -o - %s | FileCheck -check-prefix=GCN %s
+
+# GCN-LABEL: name: hazard_vcmpx_sdwa_permlane16
+# GCN:      V_CMPX_LE_F32_nosdst_sdwa
+# GCN:      S_ADD_U32
+# GCN-NEXT: $vgpr1 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
+# GCN-NEXT: V_PERMLANE16_B32_e64
+---
+name:            hazard_vcmpx_sdwa_permlane16
+body:            |
+  bb.0:
+    successors: %bb.1
+    $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+    V_CMPX_LE_F32_nosdst_sdwa 0, $vgpr0, 0, $vgpr0, 0, 0, implicit-def $exec, implicit $mode, implicit $exec
+    S_BRANCH %bb.1
+
+  bb.1:
+    $vgpr1 = IMPLICIT_DEF
+    $vgpr2 = IMPLICIT_DEF
+    $sgpr0 = IMPLICIT_DEF
+    $sgpr1 = S_ADD_U32 $sgpr0, 0, implicit-def $scc
+    $vgpr1 = V_PERMLANE16_B32_e64 0, killed $vgpr1, 0, killed $sgpr1, 0, killed $sgpr0, $vgpr1, 0, implicit $exec
+    S_ENDPGM 0
+...

diff  --git a/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard.mir b/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard.mir
index b11c507f5580..534a9c1c01ca 100644
--- a/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard.mir
+++ b/llvm/test/CodeGen/AMDGPU/vcmpx-permlane-hazard.mir
@@ -144,3 +144,26 @@ body:            |
     $vgpr1 = V_PERMLANE16_B32_e64 0, undef $vgpr1, 0, killed $sgpr1, 0, killed $sgpr0, undef $vgpr1, 0, implicit $exec
     S_ENDPGM 0
 ...
+
+# GCN-LABEL: name: hazard_vcmpx_e64_permlane16
+# GCN:      V_CMPX_LE_F32_nosdst_e64
+# GCN:      S_ADD_U32
+# GCN-NEXT: $vgpr1 = V_MOV_B32_e32 killed $vgpr1, implicit $exec
+# GCN-NEXT: V_PERMLANE16_B32_e64
+---
+name:            hazard_vcmpx_e64_permlane16
+body:            |
+  bb.0:
+    successors: %bb.1
+    $vgpr0 = V_MOV_B32_e32 0, implicit $exec
+    V_CMPX_LE_F32_nosdst_e64 0, 0, 0, $vgpr0, 0, implicit-def $exec, implicit $mode, implicit $exec
+    S_BRANCH %bb.1
+
+  bb.1:
+    $vgpr1 = IMPLICIT_DEF
+    $vgpr2 = IMPLICIT_DEF
+    $sgpr0 = IMPLICIT_DEF
+    $sgpr1 = S_ADD_U32 $sgpr0, 0, implicit-def $scc
+    $vgpr1 = V_PERMLANE16_B32_e64 0, killed $vgpr1, 0, killed $sgpr1, 0, killed $sgpr0, $vgpr1, 0, implicit $exec
+    S_ENDPGM 0
+...