[PATCH] D98888: [AMDGPU] SIOptimizeExecMaskingPreRA should check constant bus constraint when folds EXEC copy

[Alexander via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGdccf83acf955: [AMDGPU] SIOptimizeExecMaskingPreRA should check constant bus constraint when… (authored by alex-t).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D98888/new/

https://reviews.llvm.org/D98888

Files:
  llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
  llvm/test/CodeGen/AMDGPU/opt_exec_copy_fold.mir


Index: llvm/test/CodeGen/AMDGPU/opt_exec_copy_fold.mir
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AMDGPU/opt_exec_copy_fold.mir
@@ -0,0 +1,23 @@
+# RUN: llc -run-pass si-optimize-exec-masking-pre-ra -march=amdgcn -verify-machineinstrs -o - %s | FileCheck --check-prefixes=GCN %s
+---
+# GCN-LABEL: name: opt_exec_copy_fold
+# GCN:             %2:vreg_64 = COPY $exec
+name:            opt_exec_copy_fold
+tracksRegLiveness: true
+liveins:
+  - { reg: '$sgpr0_sgpr1' }
+body:             |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    %0:vgpr_32 = V_CNDMASK_B32_e64 0, 0, 0, 1, $sgpr0_sgpr1, implicit $exec
+    %1:sreg_64 = V_CMP_NE_U32_e64 0, %0, implicit $exec
+    %2:vreg_64 = COPY $exec
+    %3:sreg_64 = V_CMP_EQ_U64_e64 %1, %2, implicit $exec
+    $scc = COPY %3
+    S_CBRANCH_SCC0 %bb.1, implicit $scc
+  
+  bb.1:
+...
+
+
Index: llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
===================================================================
--- llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
+++ llvm/lib/Target/AMDGPU/SIOptimizeExecMaskingPreRA.cpp
@@ -416,15 +416,20 @@
         continue;
 
       Register SavedExec = I->getOperand(0).getReg();
-      if (SavedExec.isVirtual() && MRI->hasOneNonDBGUse(SavedExec) &&
-          MRI->use_instr_nodbg_begin(SavedExec)->getParent() ==
-              I->getParent()) {
-        LLVM_DEBUG(dbgs() << "Redundant EXEC COPY: " << *I << '\n');
-        LIS->RemoveMachineInstrFromMaps(*I);
-        I->eraseFromParent();
-        MRI->replaceRegWith(SavedExec, ExecReg);
-        LIS->removeInterval(SavedExec);
-        Changed = true;
+      if (SavedExec.isVirtual() && MRI->hasOneNonDBGUse(SavedExec)) {
+        MachineInstr *SingleExecUser = &*MRI->use_instr_nodbg_begin(SavedExec);
+        int Idx = SingleExecUser->findRegisterUseOperandIdx(SavedExec);
+        assert(Idx != -1);
+        if (SingleExecUser->getParent() == I->getParent() &&
+            !SingleExecUser->getOperand(Idx).isImplicit() &&
+            TII->isOperandLegal(*SingleExecUser, Idx, &I->getOperand(1))) {
+          LLVM_DEBUG(dbgs() << "Redundant EXEC COPY: " << *I << '\n');
+          LIS->RemoveMachineInstrFromMaps(*I);
+          I->eraseFromParent();
+          MRI->replaceRegWith(SavedExec, ExecReg);
+          LIS->removeInterval(SavedExec);
+          Changed = true;
+        }
       }
       break;
     }


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