[llvm-branch-commits] [llvm] [RegAlloc][NewPM] Plug Greedy RA in codegen pipeline (PR #120557)

Thu Dec 19 07:01:20 PST 2024

llvmbot wrote:




@llvm/pr-subscribers-backend-systemz

Author: Akshat Oke (optimisan)

<details>
<summary>Changes</summary>


Use `-passes="regallocgreedy<[all|sgpr|wwm|vgpr]>` to insert the greedy RA with a filter and `-regalloc-npm=<type>` to control which RA to use in existing pipeline.

`-regalloc-npm=<type>` is not for AMDGPU. Adding options like `sgpr-regalloc-npm` for it next.

---
Full diff: https://github.com/llvm/llvm-project/pull/120557.diff


18 Files Affected:

- (modified) llvm/include/llvm/Passes/CodeGenPassBuilder.h (+32-14) 
- (modified) llvm/include/llvm/Passes/MachinePassRegistry.def (+2-2) 
- (modified) llvm/include/llvm/Target/CGPassBuilderOption.h (+2-2) 
- (modified) llvm/lib/Passes/PassBuilder.cpp (+14) 
- (modified) llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp (+23) 
- (modified) llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h (+2) 
- (modified) llvm/test/CodeGen/AArch64/implicit-def-remat-requires-impdef-check.mir (+1) 
- (modified) llvm/test/CodeGen/AArch64/implicit-def-with-impdef-greedy-assert.mir (+1) 
- (modified) llvm/test/CodeGen/AArch64/pr51516.mir (+1) 
- (modified) llvm/test/CodeGen/AArch64/spill-fold.mir (+2) 
- (modified) llvm/test/CodeGen/AMDGPU/extend-phi-subrange-not-in-parent.mir (+1) 
- (modified) llvm/test/CodeGen/AMDGPU/sgpr-regalloc-flags.ll (+3) 
- (modified) llvm/test/CodeGen/MIR/Generic/runPass.mir (+1) 
- (modified) llvm/test/CodeGen/SystemZ/clear-liverange-spillreg.mir (+1) 
- (modified) llvm/test/CodeGen/Thumb/high-reg-clobber.mir (+1) 
- (modified) llvm/test/CodeGen/X86/limit-split-cost.mir (+1) 
- (modified) llvm/test/tools/llc/new-pm/regalloc-amdgpu.mir (+11-6) 
- (modified) llvm/tools/llc/NewPMDriver.cpp (+11-4) 


``````````diff

diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 28768a72c83fa3..2dbcd7122f6aa8 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -1059,7 +1059,7 @@ 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.
 template <typename Derived, typename TargetMachineT>
 void CodeGenPassBuilder<Derived, TargetMachineT>::addTargetRegisterAllocator(
     AddMachinePass &addPass, bool Optimized) const {
@@ -1075,7 +1075,22 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addTargetRegisterAllocator(
 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.
+  derived().addTargetRegisterAllocator(addPass, Optimized);
 }
 
 template <typename Derived, typename TargetMachineT>
@@ -1146,20 +1161,23 @@ 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.
+    // FIXME: This is not really an error.
+    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 5facdfa825e4cb..abcc248334ed5f 100644
--- a/llvm/include/llvm/Passes/MachinePassRegistry.def
+++ b/llvm/include/llvm/Passes/MachinePassRegistry.def
@@ -188,12 +188,12 @@ MACHINE_FUNCTION_PASS_WITH_PARAMS(
     },
     "filter=reg-filter;no-clear-vregs")
 
+// 'all' is the default filter
 MACHINE_FUNCTION_PASS_WITH_PARAMS(
     "regallocgreedy", "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 29bdb9c1746d3c..f146cc7b8028d8 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.
@@ -53,7 +53,7 @@ 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 f64b6e0adb2b32..f9a4af486631eb 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -1315,6 +1315,20 @@ parseBoundsCheckingOptions(StringRef Params) {
   return Mode;
 }
 
+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/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
index 7256eec89008a5..952bf479827f48 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.cpp
@@ -68,6 +68,7 @@
 #include "llvm/MC/TargetRegistry.h"
 #include "llvm/Passes/PassBuilder.h"
 #include "llvm/Support/FormatVariadic.h"
+#include "llvm/Target/CGPassBuilderOption.h"
 #include "llvm/Transforms/HipStdPar/HipStdPar.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/IPO/AlwaysInliner.h"
@@ -2099,6 +2100,28 @@ void AMDGPUCodeGenPassBuilder::addMachineSSAOptimization(
   addPass(SIShrinkInstructionsPass());
 }
 
+static const char RegAllocNPMNotSupportedMessage[] =
+    "-regalloc-npm not supported with amdgcn. Use -sgpr-regalloc-npm, "
+    "-wwm-regalloc-npm, and -vgpr-regalloc-npm";
+
+Error AMDGPUCodeGenPassBuilder::addRegAssignmentOptimized(
+    AddMachinePass &addPass) const {
+  if (Opt.RegAlloc != RegAllocType::Unset)
+    report_fatal_error(RegAllocNPMNotSupportedMessage, false);
+
+  return make_error<StringError>("not implemented yet",
+                                 inconvertibleErrorCode());
+}
+
+Error AMDGPUCodeGenPassBuilder::addRegAssignmentFast(
+    AddMachinePass &addPass) const {
+  if (Opt.RegAlloc != RegAllocType::Unset)
+    report_fatal_error(RegAllocNPMNotSupportedMessage, false);
+
+  return make_error<StringError>("not implemented yet",
+                                 inconvertibleErrorCode());
+}
+
 bool AMDGPUCodeGenPassBuilder::isPassEnabled(const cl::opt<bool> &Opt,
                                              CodeGenOptLevel Level) const {
   if (Opt.getNumOccurrences())
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
index 5ba58a92621edb..197476a0f80574 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetMachine.h
@@ -176,6 +176,8 @@ class AMDGPUCodeGenPassBuilder
   void addAsmPrinter(AddMachinePass &, CreateMCStreamer) const;
   Error addInstSelector(AddMachinePass &) const;
   void addMachineSSAOptimization(AddMachinePass &) const;
+  Error addRegAssignmentOptimized(AddMachinePass &) const;
+  Error addRegAssignmentFast(AddMachinePass &) const;
 
   /// Check if a pass is enabled given \p Opt option. The option always
   /// overrides defaults if explicitly used. Otherwise its default will be used
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 47aa34e3c01156..a168c2891c7d6f 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=regallocgreedy -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 a5d74ef75f0a0a..d9edda47638a3f 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=regallocgreedy -o - %s | FileCheck %s
 
 ---
 name:            widget
diff --git a/llvm/test/CodeGen/AArch64/pr51516.mir b/llvm/test/CodeGen/AArch64/pr51516.mir
index 910bfb858b50f6..e84f0ca2015ce5 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=regallocgreedy -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 b1e7ebe3a7e82b..2773b5f19618a9 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=regallocgreedy -o - %s | FileCheck %s
+# RUN: llc -mtriple=aarch64_be-none-linux-gnu -passes=regallocgreedy -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/AMDGPU/extend-phi-subrange-not-in-parent.mir b/llvm/test/CodeGen/AMDGPU/extend-phi-subrange-not-in-parent.mir
index 760ae6032230f5..42bba4d1504013 100644
--- a/llvm/test/CodeGen/AMDGPU/extend-phi-subrange-not-in-parent.mir
+++ b/llvm/test/CodeGen/AMDGPU/extend-phi-subrange-not-in-parent.mir
@@ -1,5 +1,6 @@
 # NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
 # RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a -verify-regalloc -run-pass=greedy -o - %s | FileCheck %s
+# RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx90a -verify-regalloc -passes=regallocgreedy -o - %s | FileCheck %s
 
 # Initially %2 starts out with 2 subranges (one for sub0, and one for
 # the rest of the lanes). After %2 is split, after refineSubRanges the
diff --git a/llvm/test/CodeGen/AMDGPU/sgpr-regalloc-flags.ll b/llvm/test/CodeGen/AMDGPU/sgpr-regalloc-flags.ll
index 52ad7e5355207d..a54fee3a0f964c 100644
--- a/llvm/test/CodeGen/AMDGPU/sgpr-regalloc-flags.ll
+++ b/llvm/test/CodeGen/AMDGPU/sgpr-regalloc-flags.ll
@@ -12,8 +12,11 @@
 ; RUN: not --crash llc -verify-machineinstrs=0 -regalloc=basic -mtriple=amdgcn-amd-amdhsa -debug-pass=Structure -o /dev/null %s 2>&1 | FileCheck -check-prefix=REGALLOC %s
 ; RUN: not --crash llc -verify-machineinstrs=0 -regalloc=fast -O0 -mtriple=amdgcn-amd-amdhsa -debug-pass=Structure -o /dev/null %s 2>&1 | FileCheck -check-prefix=REGALLOC %s
 
+; RUN: not llc -enable-new-pm -verify-machineinstrs=0 -regalloc-npm=fast -O0 -mtriple=amdgcn-amd-amdhsa -o /dev/null %s 2>&1 | FileCheck -check-prefix=REGALLOC-NPM %s
+; RUN: not llc -enable-new-pm -verify-machineinstrs=0 -regalloc-npm=basic -O3 -mtriple=amdgcn-amd-amdhsa -o /dev/null %s 2>&1 | FileCheck -check-prefix=REGALLOC-NPM %s
 
 ; REGALLOC: -regalloc not supported with amdgcn. Use -sgpr-regalloc, -wwm-regalloc, and -vgpr-regalloc
+; REGALLOC-NPM: -regalloc-npm not supported with amdgcn. Use -sgpr-regalloc-npm, -wwm-regalloc-npm, and -vgpr-regalloc-npm
 
 ; DEFAULT: Greedy Register Allocator
 ; DEFAULT-NEXT: Virtual Register Rewriter
diff --git a/llvm/test/CodeGen/MIR/Generic/runPass.mir b/llvm/test/CodeGen/MIR/Generic/runPass.mir
index 75763c5389b09e..41dd98ff909b0c 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=regallocgreedy -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 197c3d8551fc38..de0db97f14bf3c 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=regallocgreedy
 #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 1402c7c2cbca36..e085e38ae5fe31 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=regallocgreedy %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 7ec0404e0f737c..eec8a3939151a6 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=regallocgreedy %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/test/tools/llc/new-pm/regalloc-amdgpu.mir b/llvm/test/tools/llc/new-pm/regalloc-amdgpu.mir
index 07f2d350ffd9c0..66c9d8942f3da4 100644
--- a/llvm/test/tools/llc/new-pm/regalloc-amdgpu.mir
+++ b/llvm/test/tools/llc/new-pm/regalloc-amdgpu.mir
@@ -1,12 +1,17 @@
 # REQUIRES: amdgpu-registered-target
-# RUN: llc -mtriple=amdgcn --passes='regallocfast<filter=sgpr>,regallocfast<filter=wwm>,regallocfast<filter=vgpr>' --print-pipeline-passes --filetype=null %s | FileCheck %s --check-prefix=PASS
-# RUN: not llc -mtriple=amdgcn --passes='regallocfast<filter=bad-filter>' --print-pipeline-passes --filetype=null %s 2>&1 | FileCheck %s --check-prefix=BAD-FILTER
+# RUN: llc -mtriple=amdgcn --passes='regallocfast<filter=sgpr>,regallocfast<filter=wwm>,regallocfast<filter=vgpr>' --print-pipeline-passes --filetype=null %s | FileCheck %s --check-prefix=RAFAST
+# RUN: not llc -mtriple=amdgcn --passes='regallocfast<filter=bad-filter>' --print-pipeline-passes --filetype=null %s 2>&1 | FileCheck %s --check-prefix=RAFAST-BAD-FILTER
 
-# PASS: regallocfast<filter=sgpr>
-# PASS: regallocfast<filter=wwm>
-# PASS: regallocfast<filter=vgpr>
-# BAD-FILTER: invalid regallocfast register filter 'bad-filter'
+# RUN: llc -mtriple=amdgcn -passes='regallocgreedy<sgpr>' --print-pipeline-passes --filetype=null %s | FileCheck %s --check-prefix=RAGREEDY
+# RUN: not llc -mtriple=amdgcn -passes='regallocgreedy<bad-filter>' --print-pipeline-passes --filetype=null %s 2>&1 | FileCheck %s --check-prefix=RAGREEDY-BAD-FILTER
 
+# RAFAST: regallocfast<filter=sgpr>
+# RAFAST: regallocfast<filter=wwm>
+# RAFAST: regallocfast<filter=vgpr>
+# RAFAST-BAD-FILTER: invalid regallocfast register filter 'bad-filter'
+
+# RAGREEDY: regallocgreedy<sgpr>
+# RAGREEDY-BAD-FILTER: invalid regallocgreedy register filter 'bad-filter'
 ---
 name: f
 ...
diff --git a/llvm/tools/llc/NewPMDriver.cpp b/llvm/tools/llc/NewPMDriver.cpp
index 3892fbb8c74f78..0f7aa6284962a2 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,

``````````

</details>


https://github.com/llvm/llvm-project/pull/120557
