[llvm] 7022498 - AMDGPU/NewPM: Start implementing addCodeGenPrepare (#102816)

[via llvm-commits]

Author: Matt Arsenault
Date: 2024-08-20T00:10:45+04:00
New Revision: 7022498ac2f236e411e8a0f9a48669e754000a4b

URL: https://github.com/llvm/llvm-project/commit/7022498ac2f236e411e8a0f9a48669e754000a4b
DIFF: https://github.com/llvm/llvm-project/commit/7022498ac2f236e411e8a0f9a48669e754000a4b.diff

LOG: AMDGPU/NewPM: Start implementing addCodeGenPrepare (#102816)

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
    llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index f15d02ac9301e..04b96a32a8970 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -73,6 +73,7 @@
 #include "llvm/Transforms/Utils.h"
 #include "llvm/Transforms/Utils/FixIrreducible.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
+#include "llvm/Transforms/Utils/LowerSwitch.h"
 #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
 #include "llvm/Transforms/Utils/UnifyLoopExits.h"
 #include "llvm/Transforms/Vectorize/LoadStoreVectorizer.h"
@@ -1768,6 +1769,16 @@ AMDGPUCodeGenPassBuilder::AMDGPUCodeGenPassBuilder(
               ShadowStackGCLoweringPass>();
 }
 
+void AMDGPUCodeGenPassBuilder::addCodeGenPrepare(AddIRPass &addPass) const {
+  Base::addCodeGenPrepare(addPass);
+
+  // LowerSwitch pass may introduce unreachable blocks that can cause unexpected
+  // behavior for subsequent passes. Placing it here seems better that these
+  // blocks would get cleaned up by UnreachableBlockElim inserted next in the
+  // pass flow.
+  addPass(LowerSwitchPass());
+}
+
 void AMDGPUCodeGenPassBuilder::addPreISel(AddIRPass &addPass) const {
   const bool LateCFGStructurize = AMDGPUTargetMachine::EnableLateStructurizeCFG;
   const bool DisableStructurizer = AMDGPUTargetMachine::DisableStructurizer;

diff  --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
index 4dffddd2d44cc..576bf40e3328d 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
@@ -165,11 +165,14 @@ class AMDGPUPassConfig : public TargetPassConfig {
 
 class AMDGPUCodeGenPassBuilder
     : public CodeGenPassBuilder<AMDGPUCodeGenPassBuilder, GCNTargetMachine> {
+  using Base = CodeGenPassBuilder<AMDGPUCodeGenPassBuilder, GCNTargetMachine>;
+
 public:
   AMDGPUCodeGenPassBuilder(GCNTargetMachine &TM,
                            const CGPassBuilderOption &Opts,
                            PassInstrumentationCallbacks *PIC);
 
+  void addCodeGenPrepare(AddIRPass &) const;
   void addPreISel(AddIRPass &addPass) const;
   void addAsmPrinter(AddMachinePass &, CreateMCStreamer) const;
   Error addInstSelector(AddMachinePass &) const;