[llvm] [RISCV][NewPM] Port RISCVCodeGenPrepare to the new pass manager (PR #168381)
Alex Bradbury via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 18 22:21:44 PST 2025
https://github.com/asb updated https://github.com/llvm/llvm-project/pull/168381
>From aadfd4bbfcd912a0cf8ee9162bf19fbb492809e1 Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Fri, 14 Nov 2025 14:52:39 +0000
Subject: [PATCH 1/2] [RISCV][NewPM] Port RISCVCodeGenPrepare to the new pass
manager
As suggested in the review for #160536 it would be good to follow up and
port the RISC-V passes to the new pass manager. This PR starts that
task. It provides the bare minimum necessary to run RISCVCodeGenPrepare
with opt -passes=riscv-codegenprepare. The approach used is modeled on
my observations of the AMDGPU backend and the recent work to port the
X86 passes.
One unfortunate annoyance is that the decision to split the passes into
RISCVFoo (holds logic for implementing the pass), RISCVFooLegacyPass
(provides the legacy pass manager interface and calls into RISCVFoo),
and RISCVFooPass (provides the new pass manager interface and calls into
RISCVFoo) means we end up with a
`initializeRISCVCodeGenPrepareLegacyPassPass` function. X86 has the same
thing and lives with it. I suggest doing the same here. The naming
scheme is logical to me, and it doesn't seem worth messing with the
PassSupport.h macros.
I would appreciate a close review for the overall approach, as I intend
to follow up with patches in a similar style for the other RISC-V
passes. i.e. if you think I've somehow picked up on less desirable
naming / structuring or other features from the X86 and AMDGPU passes
I've looked at, now is the best time to speak up!
---
llvm/lib/Target/RISCV/RISCV.h | 12 ++-
llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp | 82 ++++++++++++-------
llvm/lib/Target/RISCV/RISCVPassRegistry.def | 22 +++++
llvm/lib/Target/RISCV/RISCVTargetMachine.cpp | 7 +-
.../CodeGen/RISCV/riscv-codegenprepare.ll | 1 +
5 files changed, 91 insertions(+), 33 deletions(-)
create mode 100644 llvm/lib/Target/RISCV/RISCVPassRegistry.def
diff --git a/llvm/lib/Target/RISCV/RISCV.h b/llvm/lib/Target/RISCV/RISCV.h
index 51e8e8574ed15..ec16806912c8f 100644
--- a/llvm/lib/Target/RISCV/RISCV.h
+++ b/llvm/lib/Target/RISCV/RISCV.h
@@ -26,8 +26,16 @@ class RISCVRegisterBankInfo;
class RISCVSubtarget;
class RISCVTargetMachine;
-FunctionPass *createRISCVCodeGenPreparePass();
-void initializeRISCVCodeGenPreparePass(PassRegistry &);
+class RISCVCodeGenPreparePass : public PassInfoMixin<RISCVCodeGenPreparePass> {
+private:
+ const RISCVTargetMachine &TM;
+
+public:
+ RISCVCodeGenPreparePass(const RISCVTargetMachine &TM) : TM(TM) {}
+ PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
+};
+FunctionPass *createRISCVCodeGenPrepareLegacyPass();
+void initializeRISCVCodeGenPrepareLegacyPassPass(PassRegistry &);
FunctionPass *createRISCVDeadRegisterDefinitionsPass();
void initializeRISCVDeadRegisterDefinitionsPass(PassRegistry &);
diff --git a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
index ce349598bd9b1..e983291767b8f 100644
--- a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
+++ b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
@@ -33,20 +33,33 @@ using namespace llvm;
#define PASS_NAME "RISC-V CodeGenPrepare"
namespace {
-
-class RISCVCodeGenPrepare : public FunctionPass,
- public InstVisitor<RISCVCodeGenPrepare, bool> {
+class RISCVCodeGenPrepare : public InstVisitor<RISCVCodeGenPrepare, bool> {
+ Function &F;
const DataLayout *DL;
const DominatorTree *DT;
const RISCVSubtarget *ST;
+public:
+ RISCVCodeGenPrepare(Function &F, const DominatorTree *DT,
+ const RISCVSubtarget *ST)
+ : F(F), DL(&F.getDataLayout()), DT(DT), ST(ST) {}
+ bool run();
+ bool visitInstruction(Instruction &I) { return false; }
+ bool visitAnd(BinaryOperator &BO);
+ bool visitIntrinsicInst(IntrinsicInst &I);
+ bool expandVPStrideLoad(IntrinsicInst &I);
+ bool widenVPMerge(IntrinsicInst &I);
+};
+} // namespace
+
+namespace {
+class RISCVCodeGenPrepareLegacyPass : public FunctionPass {
public:
static char ID;
- RISCVCodeGenPrepare() : FunctionPass(ID) {}
+ RISCVCodeGenPrepareLegacyPass() : FunctionPass(ID) {}
bool runOnFunction(Function &F) override;
-
StringRef getPassName() const override { return PASS_NAME; }
void getAnalysisUsage(AnalysisUsage &AU) const override {
@@ -54,15 +67,8 @@ class RISCVCodeGenPrepare : public FunctionPass,
AU.addRequired<DominatorTreeWrapperPass>();
AU.addRequired<TargetPassConfig>();
}
-
- bool visitInstruction(Instruction &I) { return false; }
- bool visitAnd(BinaryOperator &BO);
- bool visitIntrinsicInst(IntrinsicInst &I);
- bool expandVPStrideLoad(IntrinsicInst &I);
- bool widenVPMerge(IntrinsicInst &I);
};
-
-} // end anonymous namespace
+} // namespace
// Try to optimize (i64 (and (zext/sext (i32 X), C1))) if C1 has bit 31 set,
// but bits 63:32 are zero. If we know that bit 31 of X is 0, we can fill
@@ -273,17 +279,7 @@ bool RISCVCodeGenPrepare::expandVPStrideLoad(IntrinsicInst &II) {
return true;
}
-bool RISCVCodeGenPrepare::runOnFunction(Function &F) {
- if (skipFunction(F))
- return false;
-
- auto &TPC = getAnalysis<TargetPassConfig>();
- auto &TM = TPC.getTM<RISCVTargetMachine>();
- ST = &TM.getSubtarget<RISCVSubtarget>(F);
-
- DL = &F.getDataLayout();
- DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-
+bool RISCVCodeGenPrepare::run() {
bool MadeChange = false;
for (auto &BB : F)
for (Instruction &I : llvm::make_early_inc_range(BB))
@@ -292,12 +288,40 @@ bool RISCVCodeGenPrepare::runOnFunction(Function &F) {
return MadeChange;
}
-INITIALIZE_PASS_BEGIN(RISCVCodeGenPrepare, DEBUG_TYPE, PASS_NAME, false, false)
+bool RISCVCodeGenPrepareLegacyPass::runOnFunction(Function &F) {
+ if (skipFunction(F))
+ return false;
+
+ auto &TPC = getAnalysis<TargetPassConfig>();
+ auto &TM = TPC.getTM<RISCVTargetMachine>();
+ auto ST = &TM.getSubtarget<RISCVSubtarget>(F);
+ auto DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+
+ RISCVCodeGenPrepare RVCGP(F, DT, ST);
+ return RVCGP.run();
+}
+
+INITIALIZE_PASS_BEGIN(RISCVCodeGenPrepareLegacyPass, DEBUG_TYPE, PASS_NAME,
+ false, false)
INITIALIZE_PASS_DEPENDENCY(TargetPassConfig)
-INITIALIZE_PASS_END(RISCVCodeGenPrepare, DEBUG_TYPE, PASS_NAME, false, false)
+INITIALIZE_PASS_END(RISCVCodeGenPrepareLegacyPass, DEBUG_TYPE, PASS_NAME, false,
+ false)
-char RISCVCodeGenPrepare::ID = 0;
+char RISCVCodeGenPrepareLegacyPass::ID = 0;
+
+FunctionPass *llvm::createRISCVCodeGenPrepareLegacyPass() {
+ return new RISCVCodeGenPrepareLegacyPass();
+}
-FunctionPass *llvm::createRISCVCodeGenPreparePass() {
- return new RISCVCodeGenPrepare();
+PreservedAnalyses RISCVCodeGenPreparePass::run(Function &F,
+ FunctionAnalysisManager &FAM) {
+ DominatorTree *DT = &FAM.getResult<DominatorTreeAnalysis>(F);
+ auto ST = &TM.getSubtarget<RISCVSubtarget>(F);
+ bool Changed = RISCVCodeGenPrepare(F, DT, ST).run();
+ if (!Changed)
+ return PreservedAnalyses::all();
+
+ PreservedAnalyses PA = PreservedAnalyses::none();
+ PA.preserveSet<CFGAnalyses>();
+ return PA;
}
diff --git a/llvm/lib/Target/RISCV/RISCVPassRegistry.def b/llvm/lib/Target/RISCV/RISCVPassRegistry.def
new file mode 100644
index 0000000000000..32c66ffdf3cc2
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVPassRegistry.def
@@ -0,0 +1,22 @@
+//===- RISCVPassRegistry.def - Registry of RISC-V passes --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is used as the registry of passes that are part of the RISC-V
+// backend.
+//
+//===----------------------------------------------------------------------===//
+
+// NOTE: NO INCLUDE GUARD DESIRED!
+
+#ifndef FUNCTION_PASS
+#define FUNCTION_PASS(NAME, CREATE_PASS)
+#endif
+FUNCTION_PASS(
+ "riscv-codegenprepare",
+ RISCVCodeGenPreparePass(*static_cast<const RISCVTargetMachine *>(this)))
+#undef FUNCTION_PASS
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index 16ef67da83128..96de5c876caaf 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -118,7 +118,7 @@ extern "C" LLVM_ABI LLVM_EXTERNAL_VISIBILITY void LLVMInitializeRISCVTarget() {
initializeRISCVLateBranchOptPass(*PR);
initializeRISCVMakeCompressibleOptPass(*PR);
initializeRISCVGatherScatterLoweringPass(*PR);
- initializeRISCVCodeGenPreparePass(*PR);
+ initializeRISCVCodeGenPrepareLegacyPassPass(*PR);
initializeRISCVPostRAExpandPseudoPass(*PR);
initializeRISCVMergeBaseOffsetOptPass(*PR);
initializeRISCVOptWInstrsPass(*PR);
@@ -456,7 +456,7 @@ void RISCVPassConfig::addIRPasses() {
addPass(createRISCVGatherScatterLoweringPass());
addPass(createInterleavedAccessPass());
- addPass(createRISCVCodeGenPreparePass());
+ addPass(createRISCVCodeGenPrepareLegacyPass());
}
TargetPassConfig::addIRPasses();
@@ -628,6 +628,9 @@ bool RISCVPassConfig::addILPOpts() {
}
void RISCVTargetMachine::registerPassBuilderCallbacks(PassBuilder &PB) {
+#define GET_PASS_REGISTRY "RISCVPassRegistry.def"
+#include "llvm/Passes/TargetPassRegistry.inc"
+
PB.registerLateLoopOptimizationsEPCallback([=](LoopPassManager &LPM,
OptimizationLevel Level) {
if (Level != OptimizationLevel::O0)
diff --git a/llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll b/llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
index cf5d0f107359a..c25e337777631 100644
--- a/llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
+++ b/llvm/test/CodeGen/RISCV/riscv-codegenprepare.ll
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt %s -S -riscv-codegenprepare -mtriple=riscv64 | FileCheck %s
+; RUN: opt %s -S -passes=riscv-codegenprepare -mtriple=riscv64 | FileCheck %s
; Make sure we convert the 4294967294 in for.body.preheader.new to -2 based on
; the upper 33 bits being zero by the dominating condition %cmp3.
>From 1b71d50d67d31306fa529ff4aa093134dfec0b20 Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb at igalia.com>
Date: Wed, 19 Nov 2025 06:21:16 +0000
Subject: [PATCH 2/2] As requested in review, make RISCVTargetMachine a pointer
rather than ref
---
llvm/lib/Target/RISCV/RISCV.h | 4 ++--
llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp | 2 +-
llvm/lib/Target/RISCV/RISCVPassRegistry.def | 4 +---
3 files changed, 4 insertions(+), 6 deletions(-)
diff --git a/llvm/lib/Target/RISCV/RISCV.h b/llvm/lib/Target/RISCV/RISCV.h
index ec16806912c8f..938c62e4f9f94 100644
--- a/llvm/lib/Target/RISCV/RISCV.h
+++ b/llvm/lib/Target/RISCV/RISCV.h
@@ -28,10 +28,10 @@ class RISCVTargetMachine;
class RISCVCodeGenPreparePass : public PassInfoMixin<RISCVCodeGenPreparePass> {
private:
- const RISCVTargetMachine &TM;
+ const RISCVTargetMachine *TM;
public:
- RISCVCodeGenPreparePass(const RISCVTargetMachine &TM) : TM(TM) {}
+ RISCVCodeGenPreparePass(const RISCVTargetMachine *TM) : TM(TM) {}
PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
};
FunctionPass *createRISCVCodeGenPrepareLegacyPass();
diff --git a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
index e983291767b8f..ab450f9c4a61d 100644
--- a/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
+++ b/llvm/lib/Target/RISCV/RISCVCodeGenPrepare.cpp
@@ -316,7 +316,7 @@ FunctionPass *llvm::createRISCVCodeGenPrepareLegacyPass() {
PreservedAnalyses RISCVCodeGenPreparePass::run(Function &F,
FunctionAnalysisManager &FAM) {
DominatorTree *DT = &FAM.getResult<DominatorTreeAnalysis>(F);
- auto ST = &TM.getSubtarget<RISCVSubtarget>(F);
+ auto ST = &TM->getSubtarget<RISCVSubtarget>(F);
bool Changed = RISCVCodeGenPrepare(F, DT, ST).run();
if (!Changed)
return PreservedAnalyses::all();
diff --git a/llvm/lib/Target/RISCV/RISCVPassRegistry.def b/llvm/lib/Target/RISCV/RISCVPassRegistry.def
index 32c66ffdf3cc2..29ccf2cff1ca5 100644
--- a/llvm/lib/Target/RISCV/RISCVPassRegistry.def
+++ b/llvm/lib/Target/RISCV/RISCVPassRegistry.def
@@ -16,7 +16,5 @@
#ifndef FUNCTION_PASS
#define FUNCTION_PASS(NAME, CREATE_PASS)
#endif
-FUNCTION_PASS(
- "riscv-codegenprepare",
- RISCVCodeGenPreparePass(*static_cast<const RISCVTargetMachine *>(this)))
+FUNCTION_PASS("riscv-codegenprepare", RISCVCodeGenPreparePass(this))
#undef FUNCTION_PASS
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