SPIRV: Set NoPHIs property after rewriting them

[arsenm]

There should be no PHIs after selection, as OpPhi is used
instead. This hopefully avoids errors in #135277.

[arsenm]

• SPIRV: Set NoPHIs property after rewriting them #136327 👈 (View in Graphite)
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[llvmbot]

@llvm/pr-subscribers-backend-spir-v

Author: Matt Arsenault (arsenm)

Changes

There should be no PHIs after selection, as OpPhi is used
instead. This hopefully avoids errors in #135277.

---

Full diff: https://github.com/llvm/llvm-project/pull/136327.diff

1 Files Affected:

• (modified) llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp (+6)

diff --git a/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp b/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
index 68286737b972f..f30578767a939 100644
--- a/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp
@@ -269,6 +269,12 @@ class SPIRVInstructionSelect : public InstructionSelect {
     return InstructionSelect::getRequiredProperties().reset(
         MachineFunctionProperties::Property::RegBankSelected);
   }
+
+  MachineFunctionProperties getClearedProperties() const override {
+    // No generic Phis remain, replaced with OpPhi
+    return InstructionSelect::getClearedProperties().reset(
+        MachineFunctionProperties::Property::NoPHIs);
+  }
 };
 } // namespace
 

[mikhailramalho]

The errors mentioned in PR #135277 still happen if we apply the patch here without 1293477:

Failed Tests (15):
  LLVM :: CodeGen/AArch64/fast-isel-cmp-vec.ll
  LLVM :: CodeGen/AArch64/wineh4.mir
  LLVM :: CodeGen/AArch64/wineh8.mir
  LLVM :: CodeGen/SPIRV/assume.ll
  LLVM :: CodeGen/SPIRV/expect.ll
  LLVM :: CodeGen/SPIRV/hlsl-resources/BufferStore.ll
  LLVM :: CodeGen/SPIRV/opt-gepoperator-of-gvar.ll
  LLVM :: CodeGen/SPIRV/optimizations/add-check-overflow.ll
  LLVM :: CodeGen/SPIRV/optimizations/switch-condition-type.ll
  LLVM :: Frontend/HLSL/empty_cs_entry.ll
  LLVM-Unit :: Target/SPIRV/./SPIRVTests/40/56
  LLVM-Unit :: Target/SPIRV/./SPIRVTests/41/56
  LLVM-Unit :: Target/SPIRV/./SPIRVTests/42/56
  LLVM-Unit :: Target/SPIRV/./SPIRVTests/43/56
  LLVM-Unit :: Target/SPIRV/./SPIRVTests/49/56

[VyacheslavLevytskyy]

@arsenm We currently do not select OpPhi during the instruction selection pass, instead we keep PHI until the module layout finalization stage (introduced as one of improvements in #119202 -- https://github.com/VyacheslavLevytskyy/llvm-project/blob/3e74d2c6983af986b70060ca44e6e1fbcb34a554/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp#L3354-L3369).