[llvm-branch-commits] [llvm] [RegAlloc][NewPM] Plug Greedy RA in codegen pipeline (PR #120557)
Akshat Oke via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Thu Feb 13 20:39:03 PST 2025
https://github.com/optimisan updated https://github.com/llvm/llvm-project/pull/120557
>From 6b013984ddb49a7c60a6eb60db33aa73f9e55c4d Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Tue, 11 Feb 2025 12:36:40 +0000
Subject: [PATCH 1/2] [CodeGen][NewPM] Plug greedy RA in codegen pipeline
---
llvm/include/llvm/Passes/CodeGenPassBuilder.h | 51 ++++++++++++++-----
.../llvm/Passes/MachinePassRegistry.def | 4 +-
.../include/llvm/Target/CGPassBuilderOption.h | 4 +-
llvm/lib/Passes/PassBuilder.cpp | 14 +++++
...plicit-def-remat-requires-impdef-check.mir | 1 +
...implicit-def-with-impdef-greedy-assert.mir | 1 +
llvm/test/CodeGen/AArch64/pr51516.mir | 1 +
llvm/test/CodeGen/AArch64/spill-fold.mir | 2 +
llvm/test/CodeGen/MIR/Generic/runPass.mir | 1 +
.../SystemZ/clear-liverange-spillreg.mir | 1 +
llvm/test/CodeGen/Thumb/high-reg-clobber.mir | 1 +
llvm/test/CodeGen/X86/limit-split-cost.mir | 1 +
llvm/tools/llc/NewPMDriver.cpp | 15 ++++--
13 files changed, 75 insertions(+), 22 deletions(-)
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index a1e81f4b7375a..31120b0b43485 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -1061,7 +1061,9 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addMachineSSAOptimization(
///
/// A target that uses the standard regalloc pass order for fast or optimized
/// allocation may still override this for per-target regalloc
-/// selection. But -regalloc=... always takes precedence.
+/// selection. But -regalloc-npm=... always takes precedence.
+/// If a target does not want to allow users to set -regalloc-npm=... at all,
+/// check if Opt.RegAlloc == RegAllocType::Unset.
template <typename Derived, typename TargetMachineT>
void CodeGenPassBuilder<Derived, TargetMachineT>::addTargetRegisterAllocator(
AddMachinePass &addPass, bool Optimized) const {
@@ -1074,10 +1076,29 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addTargetRegisterAllocator(
/// Find and instantiate the register allocation pass requested by this target
/// at the current optimization level. Different register allocators are
/// defined as separate passes because they may require different analysis.
+///
+/// This helper ensures that the -regalloc-npm= option is always available,
+/// even for targets that override the default allocator.
template <typename Derived, typename TargetMachineT>
void CodeGenPassBuilder<Derived, TargetMachineT>::addRegAllocPass(
AddMachinePass &addPass, bool Optimized) const {
- // TODO: Parse Opt.RegAlloc to add register allocator.
+ // Use the specified -regalloc-npm={basic|greedy|fast|pbqp}
+ if (Opt.RegAlloc > RegAllocType::Default) {
+ switch (Opt.RegAlloc) {
+ case RegAllocType::Fast:
+ addPass(RegAllocFastPass());
+ break;
+ case RegAllocType::Greedy:
+ addPass(RAGreedyPass());
+ break;
+ default:
+ report_fatal_error("register allocator not supported yet.", false);
+ }
+ return;
+ }
+ // -regalloc=default or unspecified, so pick based on the optimization level
+ // or ask the target for the regalloc pass.
+ derived().addTargetRegisterAllocator(addPass, Optimized);
}
template <typename Derived, typename TargetMachineT>
@@ -1148,20 +1169,22 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addOptimizedRegAlloc(
// PreRA instruction scheduling.
addPass(MachineSchedulerPass());
- if (derived().addRegAssignmentOptimized(addPass)) {
- // Allow targets to expand pseudo instructions depending on the choice of
- // registers before MachineCopyPropagation.
- derived().addPostRewrite(addPass);
+ if (auto E = derived().addRegAssignmentOptimized(addPass)) {
+ // addRegAssignmentOptimized did not add a reg alloc pass, so do nothing.
+ return;
+ }
+ // Allow targets to expand pseudo instructions depending on the choice of
+ // registers before MachineCopyPropagation.
+ derived().addPostRewrite(addPass);
- // Copy propagate to forward register uses and try to eliminate COPYs that
- // were not coalesced.
- addPass(MachineCopyPropagationPass());
+ // Copy propagate to forward register uses and try to eliminate COPYs that
+ // were not coalesced.
+ addPass(MachineCopyPropagationPass());
- // Run post-ra machine LICM to hoist reloads / remats.
- //
- // FIXME: can this move into MachineLateOptimization?
- addPass(MachineLICMPass());
- }
+ // Run post-ra machine LICM to hoist reloads / remats.
+ //
+ // FIXME: can this move into MachineLateOptimization?
+ addPass(MachineLICMPass());
}
//===---------------------------------------------------------------------===//
diff --git a/llvm/include/llvm/Passes/MachinePassRegistry.def b/llvm/include/llvm/Passes/MachinePassRegistry.def
index 9e2d9e071e85d..3656e5db9fb83 100644
--- a/llvm/include/llvm/Passes/MachinePassRegistry.def
+++ b/llvm/include/llvm/Passes/MachinePassRegistry.def
@@ -193,12 +193,12 @@ MACHINE_FUNCTION_PASS_WITH_PARAMS(
},
"filter=reg-filter;no-clear-vregs")
+// 'all' is the default filter
MACHINE_FUNCTION_PASS_WITH_PARAMS(
"greedy", "RAGreedyPass",
[](RAGreedyPass::Options Opts) { return RAGreedyPass(Opts); },
[PB = this](StringRef Params) {
- // TODO: parseRegAllocGreedyFilterFunc(*PB, Params);
- return Expected<RAGreedyPass::Options>(RAGreedyPass::Options{});
+ return parseRegAllocGreedyFilterFunc(*PB, Params);
}, "reg-filter"
)
#undef MACHINE_FUNCTION_PASS_WITH_PARAMS
diff --git a/llvm/include/llvm/Target/CGPassBuilderOption.h b/llvm/include/llvm/Target/CGPassBuilderOption.h
index d3d19c8a7dc9f..b496a9f66296f 100644
--- a/llvm/include/llvm/Target/CGPassBuilderOption.h
+++ b/llvm/include/llvm/Target/CGPassBuilderOption.h
@@ -20,7 +20,7 @@
namespace llvm {
enum class RunOutliner { TargetDefault, AlwaysOutline, NeverOutline };
-enum class RegAllocType { Default, Basic, Fast, Greedy, PBQP };
+enum class RegAllocType { Unset, Default, Basic, Fast, Greedy, PBQP };
// Not one-on-one but mostly corresponding to commandline options in
// TargetPassConfig.cpp.
@@ -52,7 +52,7 @@ struct CGPassBuilderOption {
bool RequiresCodeGenSCCOrder = false;
RunOutliner EnableMachineOutliner = RunOutliner::TargetDefault;
- StringRef RegAlloc = "default";
+ RegAllocType RegAlloc = RegAllocType::Unset;
std::optional<GlobalISelAbortMode> EnableGlobalISelAbort;
std::string FSProfileFile;
std::string FSRemappingFile;
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 86e669864f471..1042297e7a705 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -1412,6 +1412,20 @@ parseBoundsCheckingOptions(StringRef Params) {
return Options;
}
+Expected<RAGreedyPass::Options>
+parseRegAllocGreedyFilterFunc(PassBuilder &PB, StringRef Params) {
+ if (Params.empty() || Params == "all") {
+ return RAGreedyPass::Options();
+ }
+ std::optional<RegAllocFilterFunc> Filter = PB.parseRegAllocFilter(Params);
+ if (!Filter) {
+ return make_error<StringError>(
+ formatv("invalid regallocgreedy register filter '{0}' ", Params).str(),
+ inconvertibleErrorCode());
+ }
+ return RAGreedyPass::Options{*Filter, Params};
+}
+
} // namespace
/// Tests whether a pass name starts with a valid prefix for a default pipeline
diff --git a/llvm/test/CodeGen/AArch64/implicit-def-remat-requires-impdef-check.mir b/llvm/test/CodeGen/AArch64/implicit-def-remat-requires-impdef-check.mir
index 47aa34e3c0115..e8d0c43e81433 100644
--- a/llvm/test/CodeGen/AArch64/implicit-def-remat-requires-impdef-check.mir
+++ b/llvm/test/CodeGen/AArch64/implicit-def-remat-requires-impdef-check.mir
@@ -1,5 +1,6 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
# RUN: llc -mtriple=arm64-apple-macosx -mcpu=apple-m1 -stress-regalloc=4 -verify-regalloc -run-pass=greedy -o - %s | FileCheck %s
+# RUN: llc -mtriple=arm64-apple-macosx -mcpu=apple-m1 -stress-regalloc=4 -verify-regalloc -passes=greedy -o - %s | FileCheck %s
--- |
define void @inst_stores_to_dead_spill_implicit_def_impdef() {
diff --git a/llvm/test/CodeGen/AArch64/implicit-def-with-impdef-greedy-assert.mir b/llvm/test/CodeGen/AArch64/implicit-def-with-impdef-greedy-assert.mir
index a5d74ef75f0a0..a1caa46e8b2bb 100644
--- a/llvm/test/CodeGen/AArch64/implicit-def-with-impdef-greedy-assert.mir
+++ b/llvm/test/CodeGen/AArch64/implicit-def-with-impdef-greedy-assert.mir
@@ -1,5 +1,6 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 3
# RUN: llc -mtriple=arm64-apple-ios -run-pass=greedy -o - %s | FileCheck %s
+# RUN: llc -mtriple=arm64-apple-ios -passes=greedy -o - %s | FileCheck %s
---
name: widget
diff --git a/llvm/test/CodeGen/AArch64/pr51516.mir b/llvm/test/CodeGen/AArch64/pr51516.mir
index 910bfb858b50f..ae54ad0d5cef4 100644
--- a/llvm/test/CodeGen/AArch64/pr51516.mir
+++ b/llvm/test/CodeGen/AArch64/pr51516.mir
@@ -1,4 +1,5 @@
# RUN: llc -mtriple=aarch64-unknown-fuchsia -run-pass=greedy -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -mtriple=aarch64-unknown-fuchsia -passes=greedy -verify-machineinstrs -o - %s | FileCheck %s
# Check that we spill %31 and do not rematerialize it since the use operand
# of ADDXri is killed by the STRXui in this block.
diff --git a/llvm/test/CodeGen/AArch64/spill-fold.mir b/llvm/test/CodeGen/AArch64/spill-fold.mir
index b1e7ebe3a7e82..0149e4504bed2 100644
--- a/llvm/test/CodeGen/AArch64/spill-fold.mir
+++ b/llvm/test/CodeGen/AArch64/spill-fold.mir
@@ -1,5 +1,7 @@
# RUN: llc -mtriple=aarch64-none-linux-gnu -run-pass greedy -verify-machineinstrs -o - %s | FileCheck %s
# RUN: llc -mtriple=aarch64_be-none-linux-gnu -run-pass greedy -verify-machineinstrs -o - %s | FileCheck %s
+# RUN: llc -mtriple=aarch64-none-linux-gnu -passes=greedy -o - %s | FileCheck %s
+# RUN: llc -mtriple=aarch64_be-none-linux-gnu -passes=greedy -o - %s | FileCheck %s
--- |
define i64 @test_subreg_spill_fold() { ret i64 0 }
define i64 @test_subreg_spill_fold2() { ret i64 0 }
diff --git a/llvm/test/CodeGen/MIR/Generic/runPass.mir b/llvm/test/CodeGen/MIR/Generic/runPass.mir
index 75763c5389b09..824d9ed0e65f8 100644
--- a/llvm/test/CodeGen/MIR/Generic/runPass.mir
+++ b/llvm/test/CodeGen/MIR/Generic/runPass.mir
@@ -2,6 +2,7 @@
# RUN: llc -run-pass=regallocbasic -debug-pass=Arguments -o - %s | FileCheck %s
# RUN: llc -run-pass=regallocfast -debug-pass=Arguments -o - %s | FileCheck %s
# RUN: llc -passes=regallocfast -o - %s | FileCheck %s
+# RUN: llc -passes=greedy -o - %s | FileCheck %s
# Check that passes are initialized correctly, so that it's possible to
# use -run-pass.
diff --git a/llvm/test/CodeGen/SystemZ/clear-liverange-spillreg.mir b/llvm/test/CodeGen/SystemZ/clear-liverange-spillreg.mir
index 197c3d8551fc3..a9aecb76edcf6 100644
--- a/llvm/test/CodeGen/SystemZ/clear-liverange-spillreg.mir
+++ b/llvm/test/CodeGen/SystemZ/clear-liverange-spillreg.mir
@@ -1,4 +1,5 @@
#RUN: llc -o - %s -mtriple=s390x-ibm-linux -run-pass=greedy
+#RUN: llc -o - %s -mtriple=s390x-ibm-linux -passes=greedy
#PR34502. Check HoistSpill works properly after the live range of spilled
#virtual register is cleared.
--- |
diff --git a/llvm/test/CodeGen/Thumb/high-reg-clobber.mir b/llvm/test/CodeGen/Thumb/high-reg-clobber.mir
index 1402c7c2cbca3..6897aa7f34f94 100644
--- a/llvm/test/CodeGen/Thumb/high-reg-clobber.mir
+++ b/llvm/test/CodeGen/Thumb/high-reg-clobber.mir
@@ -3,6 +3,7 @@
# RUN: llc -mtriple thumbv6m-arm-none-eabi -run-pass greedy %s -o - | FileCheck %s
# RUN: llc -mtriple thumbv6m-arm-none-eabi -run-pass regallocfast %s -o - | FileCheck %s --check-prefix=FAST
# RUN: llc -mtriple thumbv6m-arm-none-eabi -passes=regallocfast %s -o - | FileCheck %s --check-prefix=FAST
+# RUN: llc -mtriple thumbv6m-arm-none-eabi -passes=greedy %s -o - | FileCheck %s
...
---
diff --git a/llvm/test/CodeGen/X86/limit-split-cost.mir b/llvm/test/CodeGen/X86/limit-split-cost.mir
index 7ec0404e0f737..5b8bb98389c02 100644
--- a/llvm/test/CodeGen/X86/limit-split-cost.mir
+++ b/llvm/test/CodeGen/X86/limit-split-cost.mir
@@ -1,5 +1,6 @@
# REQUIRES: asserts
# RUN: llc -mtriple=x86_64-- -run-pass=greedy %s -debug-only=regalloc -huge-size-for-split=0 -o /dev/null 2>&1 | FileCheck %s
+# RUN: llc -mtriple=x86_64-- -passes=greedy %s -debug-only=regalloc -huge-size-for-split=0 -o /dev/null 2>&1 | FileCheck %s
# Check no global region split is needed because the live range to split is trivially rematerializable.
# CHECK-NOT: Compact region bundles
--- |
diff --git a/llvm/tools/llc/NewPMDriver.cpp b/llvm/tools/llc/NewPMDriver.cpp
index 3892fbb8c74f7..0f7aa6284962a 100644
--- a/llvm/tools/llc/NewPMDriver.cpp
+++ b/llvm/tools/llc/NewPMDriver.cpp
@@ -48,10 +48,17 @@
using namespace llvm;
-static cl::opt<std::string>
- RegAlloc("regalloc-npm",
- cl::desc("Register allocator to use for new pass manager"),
- cl::Hidden, cl::init("default"));
+static cl::opt<RegAllocType> RegAlloc(
+ "regalloc-npm", cl::desc("Register allocator to use for new pass manager"),
+ cl::Hidden, cl::init(RegAllocType::Unset),
+ cl::values(
+ clEnumValN(RegAllocType::Default, "default",
+ "Default register allocator"),
+ clEnumValN(RegAllocType::PBQP, "pbqp", "PBQP register allocator"),
+ clEnumValN(RegAllocType::Fast, "fast", "Fast register allocator"),
+ clEnumValN(RegAllocType::Basic, "basic", "Basic register allocator"),
+ clEnumValN(RegAllocType::Greedy, "greedy",
+ "Greedy register allocator")));
static cl::opt<bool>
DebugPM("debug-pass-manager", cl::Hidden,
>From dd272d2263b2b861c5b2e43424a8357de3ed4d46 Mon Sep 17 00:00:00 2001
From: Akshat Oke <Akshat.Oke at amd.com>
Date: Fri, 14 Feb 2025 04:38:32 +0000
Subject: [PATCH 2/2] review
---
llvm/include/llvm/Passes/CodeGenPassBuilder.h | 2 +-
llvm/lib/Passes/PassBuilder.cpp | 10 +++++-----
2 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 31120b0b43485..5b561b83365d0 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -1092,7 +1092,7 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addRegAllocPass(
addPass(RAGreedyPass());
break;
default:
- report_fatal_error("register allocator not supported yet.", false);
+ report_fatal_error("register allocator not supported yet", false);
}
return;
}
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 1042297e7a705..607f5023dd3c0 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -1418,12 +1418,12 @@ parseRegAllocGreedyFilterFunc(PassBuilder &PB, StringRef Params) {
return RAGreedyPass::Options();
}
std::optional<RegAllocFilterFunc> Filter = PB.parseRegAllocFilter(Params);
- if (!Filter) {
- return make_error<StringError>(
- formatv("invalid regallocgreedy register filter '{0}' ", Params).str(),
- inconvertibleErrorCode());
+ if (Filter) {
+ return RAGreedyPass::Options{*Filter, Params};
}
- return RAGreedyPass::Options{*Filter, Params};
+ return make_error<StringError>(
+ formatv("invalid regallocgreedy register filter '{0}' ", Params).str(),
+ inconvertibleErrorCode());
}
} // namespace
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