[llvm] [CodeGen][NPM] Port UnreachableMachineBlockElim to NPM (PR #136127)
Akshat Oke via llvm-commits
llvm-commits at lists.llvm.org
Thu Apr 17 04:10:49 PDT 2025
https://github.com/optimisan updated https://github.com/llvm/llvm-project/pull/136127
>From 8d3c61a25d0f3af517afd9cdd92c7622e227d135 Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Thu, 17 Apr 2025 11:03:28 +0000
Subject: [PATCH] [CodeGen][NPM] Port UnreachableMachineBlockElim to NPM
---
.../llvm/CodeGen/UnreachableBlockElim.h | 8 +++
llvm/include/llvm/InitializePasses.h | 2 +-
llvm/include/llvm/Passes/CodeGenPassBuilder.h | 15 +++++
.../llvm/Passes/MachinePassRegistry.def | 2 +
llvm/lib/CodeGen/CodeGen.cpp | 2 +-
llvm/lib/CodeGen/LiveVariables.cpp | 2 +-
llvm/lib/CodeGen/UnreachableBlockElim.cpp | 67 ++++++++++++++-----
llvm/lib/Passes/PassBuilder.cpp | 1 +
.../Hexagon/unreachable-mbb-phi-subreg.mir | 1 +
.../MIR/X86/unreachable-block-call-site.mir | 1 +
10 files changed, 81 insertions(+), 20 deletions(-)
diff --git a/llvm/include/llvm/CodeGen/UnreachableBlockElim.h b/llvm/include/llvm/CodeGen/UnreachableBlockElim.h
index 7dbae77e34401..3c2b701512df6 100644
--- a/llvm/include/llvm/CodeGen/UnreachableBlockElim.h
+++ b/llvm/include/llvm/CodeGen/UnreachableBlockElim.h
@@ -22,6 +22,7 @@
#ifndef LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H
#define LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H
+#include "llvm/CodeGen/MachinePassManager.h"
#include "llvm/IR/PassManager.h"
namespace llvm {
@@ -31,6 +32,13 @@ class UnreachableBlockElimPass
public:
PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
};
+
+class UnreachableMachineBlockElimPass
+ : public PassInfoMixin<UnreachableMachineBlockElimPass> {
+public:
+ PreservedAnalyses run(MachineFunction &F, MachineFunctionAnalysisManager &AM);
+};
+
} // end namespace llvm
#endif // LLVM_CODEGEN_UNREACHABLEBLOCKELIM_H
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 9fd8f8228a717..9bef8e496c57e 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -315,7 +315,7 @@ void initializeUniformityInfoWrapperPassPass(PassRegistry &);
void initializeUnifyLoopExitsLegacyPassPass(PassRegistry &);
void initializeUnpackMachineBundlesPass(PassRegistry &);
void initializeUnreachableBlockElimLegacyPassPass(PassRegistry &);
-void initializeUnreachableMachineBlockElimPass(PassRegistry &);
+void initializeUnreachableMachineBlockElimLegacyPass(PassRegistry &);
void initializeVerifierLegacyPassPass(PassRegistry &);
void initializeVirtRegMapWrapperLegacyPass(PassRegistry &);
void initializeVirtRegRewriterPass(PassRegistry &);
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index d092049022623..61e377de0c424 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -47,6 +47,7 @@
#include "llvm/CodeGen/JMCInstrumenter.h"
#include "llvm/CodeGen/LiveDebugValuesPass.h"
#include "llvm/CodeGen/LiveIntervals.h"
+#include "llvm/CodeGen/LiveVariables.h"
#include "llvm/CodeGen/LocalStackSlotAllocation.h"
#include "llvm/CodeGen/LowerEmuTLS.h"
#include "llvm/CodeGen/MIRPrinter.h"
@@ -1172,7 +1173,21 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addOptimizedRegAlloc(
addPass(ProcessImplicitDefsPass());
+ // LiveVariables currently requires pure SSA form.
+ //
+ // FIXME: Once TwoAddressInstruction pass no longer uses kill flags,
+ // LiveVariables can be removed completely, and LiveIntervals can be directly
+ // computed. (We still either need to regenerate kill flags after regalloc, or
+ // preferably fix the scavenger to not depend on them).
+ // FIXME: UnreachableMachineBlockElim is a dependant pass of LiveVariables.
+ // When LiveVariables is removed this has to be removed/moved either.
+ // Explicit addition of UnreachableMachineBlockElim allows stopping before or
+ // after it with -stop-before/-stop-after.
+ addPass(UnreachableMachineBlockElimPass());
+ addPass(RequireAnalysisPass<LiveVariablesAnalysis, MachineFunction>());
+
// Edge splitting is smarter with machine loop info.
+ addPass(RequireAnalysisPass<MachineLoopAnalysis, MachineFunction>());
addPass(PHIEliminationPass());
// Eventually, we want to run LiveIntervals before PHI elimination.
diff --git a/llvm/include/llvm/Passes/MachinePassRegistry.def b/llvm/include/llvm/Passes/MachinePassRegistry.def
index fff5083caad1a..8c22a28eba277 100644
--- a/llvm/include/llvm/Passes/MachinePassRegistry.def
+++ b/llvm/include/llvm/Passes/MachinePassRegistry.def
@@ -194,6 +194,8 @@ MACHINE_FUNCTION_PASS("stack-slot-coloring", StackSlotColoringPass())
MACHINE_FUNCTION_PASS("tailduplication", TailDuplicatePass())
MACHINE_FUNCTION_PASS("trigger-verifier-error", TriggerVerifierErrorPass())
MACHINE_FUNCTION_PASS("two-address-instruction", TwoAddressInstructionPass())
+MACHINE_FUNCTION_PASS("unreachable-mbb-elimination",
+ UnreachableMachineBlockElimPass())
MACHINE_FUNCTION_PASS("verify", MachineVerifierPass())
MACHINE_FUNCTION_PASS("verify<machine-trace-metrics>", MachineTraceMetricsVerifierPass())
MACHINE_FUNCTION_PASS("xray-instrumentation", XRayInstrumentationPass())
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 2b0e93803971f..a34adcf4803c5 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -140,7 +140,7 @@ void llvm::initializeCodeGen(PassRegistry &Registry) {
initializeTypePromotionLegacyPass(Registry);
initializeUnpackMachineBundlesPass(Registry);
initializeUnreachableBlockElimLegacyPassPass(Registry);
- initializeUnreachableMachineBlockElimPass(Registry);
+ initializeUnreachableMachineBlockElimLegacyPass(Registry);
initializeVirtRegMapWrapperLegacyPass(Registry);
initializeVirtRegRewriterPass(Registry);
initializeWasmEHPreparePass(Registry);
diff --git a/llvm/lib/CodeGen/LiveVariables.cpp b/llvm/lib/CodeGen/LiveVariables.cpp
index ab95200af00e0..f8e0583839b23 100644
--- a/llvm/lib/CodeGen/LiveVariables.cpp
+++ b/llvm/lib/CodeGen/LiveVariables.cpp
@@ -61,7 +61,7 @@ char LiveVariablesWrapperPass::ID = 0;
char &llvm::LiveVariablesID = LiveVariablesWrapperPass::ID;
INITIALIZE_PASS_BEGIN(LiveVariablesWrapperPass, "livevars",
"Live Variable Analysis", false, false)
-INITIALIZE_PASS_DEPENDENCY(UnreachableMachineBlockElim)
+INITIALIZE_PASS_DEPENDENCY(UnreachableMachineBlockElimLegacy)
INITIALIZE_PASS_END(LiveVariablesWrapperPass, "livevars",
"Live Variable Analysis", false, false)
diff --git a/llvm/lib/CodeGen/UnreachableBlockElim.cpp b/llvm/lib/CodeGen/UnreachableBlockElim.cpp
index aa4ccec3338a9..f9f7b47160b6c 100644
--- a/llvm/lib/CodeGen/UnreachableBlockElim.cpp
+++ b/llvm/lib/CodeGen/UnreachableBlockElim.cpp
@@ -72,32 +72,58 @@ PreservedAnalyses UnreachableBlockElimPass::run(Function &F,
}
namespace {
- class UnreachableMachineBlockElim : public MachineFunctionPass {
- bool runOnMachineFunction(MachineFunction &F) override;
- void getAnalysisUsage(AnalysisUsage &AU) const override;
-
- public:
- static char ID; // Pass identification, replacement for typeid
- UnreachableMachineBlockElim() : MachineFunctionPass(ID) {}
- };
-}
-char UnreachableMachineBlockElim::ID = 0;
+class UnreachableMachineBlockElim {
+ MachineDominatorTree *MDT;
+ MachineLoopInfo *MLI;
+
+public:
+ UnreachableMachineBlockElim(MachineDominatorTree *MDT, MachineLoopInfo *MLI)
+ : MDT(MDT), MLI(MLI) {}
+ bool run(MachineFunction &MF);
+};
+
+class UnreachableMachineBlockElimLegacy : public MachineFunctionPass {
+ bool runOnMachineFunction(MachineFunction &F) override;
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+public:
+ static char ID; // Pass identification, replacement for typeid
+ UnreachableMachineBlockElimLegacy() : MachineFunctionPass(ID) {}
+};
+} // namespace
+
+char UnreachableMachineBlockElimLegacy::ID = 0;
-INITIALIZE_PASS(UnreachableMachineBlockElim, "unreachable-mbb-elimination",
- "Remove unreachable machine basic blocks", false, false)
+INITIALIZE_PASS(UnreachableMachineBlockElimLegacy,
+ "unreachable-mbb-elimination",
+ "Remove unreachable machine basic blocks", false, false)
-char &llvm::UnreachableMachineBlockElimID = UnreachableMachineBlockElim::ID;
+char &llvm::UnreachableMachineBlockElimID =
+ UnreachableMachineBlockElimLegacy::ID;
-void UnreachableMachineBlockElim::getAnalysisUsage(AnalysisUsage &AU) const {
+void UnreachableMachineBlockElimLegacy::getAnalysisUsage(
+ AnalysisUsage &AU) const {
AU.addPreserved<MachineLoopInfoWrapperPass>();
AU.addPreserved<MachineDominatorTreeWrapperPass>();
MachineFunctionPass::getAnalysisUsage(AU);
}
-bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
- df_iterator_default_set<MachineBasicBlock*> Reachable;
- bool ModifiedPHI = false;
+PreservedAnalyses
+UnreachableMachineBlockElimPass::run(MachineFunction &MF,
+ MachineFunctionAnalysisManager &AM) {
+ auto *MDT = AM.getCachedResult<MachineDominatorTreeAnalysis>(MF);
+ auto *MLI = AM.getCachedResult<MachineLoopAnalysis>(MF);
+
+ if (!UnreachableMachineBlockElim(MDT, MLI).run(MF))
+ return PreservedAnalyses::all();
+
+ return getMachineFunctionPassPreservedAnalyses()
+ .preserve<MachineLoopAnalysis>()
+ .preserve<MachineDominatorTreeAnalysis>();
+}
+bool UnreachableMachineBlockElimLegacy::runOnMachineFunction(
+ MachineFunction &MF) {
MachineDominatorTreeWrapperPass *MDTWrapper =
getAnalysisIfAvailable<MachineDominatorTreeWrapperPass>();
MachineDominatorTree *MDT = MDTWrapper ? &MDTWrapper->getDomTree() : nullptr;
@@ -105,6 +131,13 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
getAnalysisIfAvailable<MachineLoopInfoWrapperPass>();
MachineLoopInfo *MLI = MLIWrapper ? &MLIWrapper->getLI() : nullptr;
+ return UnreachableMachineBlockElim(MDT, MLI).run(MF);
+}
+
+bool UnreachableMachineBlockElim::run(MachineFunction &F) {
+ df_iterator_default_set<MachineBasicBlock *> Reachable;
+ bool ModifiedPHI = false;
+
// Mark all reachable blocks.
for (MachineBasicBlock *BB : depth_first_ext(&F, Reachable))
(void)BB/* Mark all reachable blocks */;
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index a5c624b96304b..e7057d9a6b625 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -167,6 +167,7 @@
#include "llvm/CodeGen/TargetPassConfig.h"
#include "llvm/CodeGen/TwoAddressInstructionPass.h"
#include "llvm/CodeGen/TypePromotion.h"
+#include "llvm/CodeGen/UnreachableBlockElim.h"
#include "llvm/CodeGen/VirtRegMap.h"
#include "llvm/CodeGen/WasmEHPrepare.h"
#include "llvm/CodeGen/WinEHPrepare.h"
diff --git a/llvm/test/CodeGen/Hexagon/unreachable-mbb-phi-subreg.mir b/llvm/test/CodeGen/Hexagon/unreachable-mbb-phi-subreg.mir
index 79f9d5dfffbf7..697c423d27b3f 100644
--- a/llvm/test/CodeGen/Hexagon/unreachable-mbb-phi-subreg.mir
+++ b/llvm/test/CodeGen/Hexagon/unreachable-mbb-phi-subreg.mir
@@ -1,4 +1,5 @@
# RUN: llc -mtriple=hexagon -run-pass unreachable-mbb-elimination %s -o - | FileCheck %s
+# RUN: llc -mtriple=hexagon -passes unreachable-mbb-elimination %s -o - | FileCheck %s
---
name: fred
diff --git a/llvm/test/DebugInfo/MIR/X86/unreachable-block-call-site.mir b/llvm/test/DebugInfo/MIR/X86/unreachable-block-call-site.mir
index e77192db977d7..feb5f1201f6ad 100644
--- a/llvm/test/DebugInfo/MIR/X86/unreachable-block-call-site.mir
+++ b/llvm/test/DebugInfo/MIR/X86/unreachable-block-call-site.mir
@@ -1,4 +1,5 @@
# RUN: llc -emit-call-site-info -mtriple=x86_64-pc-linux -run-pass=unreachable-mbb-elimination -o - %s | FileCheck %s
+# RUN: llc -emit-call-site-info -mtriple=x86_64-pc-linux -passes=unreachable-mbb-elimination -o - %s | FileCheck %s
# Verify that the call site information for the call residing in the eliminated
# block is removed. This test case would previously trigger an assertion when
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