[RISCV] Replace PostRAScheduler with PostMachineScheduler

[wangpc-pp]

Just like what other targets have done.

And this will make DAG mutations like MacroFusion take effect.

This PR is stacked on #68692.

[llvmbot]

@llvm/pr-subscribers-backend-risc-v

Author: Wang Pengcheng (wangpc-pp)

Changes

Just like what other targets have done.

And this will make DAG mutations like MacroFusion take effect.

This PR is stacked on #68692.

---

Full diff: https://github.com/llvm/llvm-project/pull/68696.diff

5 Files Affected:

• (modified) llvm/lib/Target/RISCV/RISCVFeatures.td (+3)
• (modified) llvm/lib/Target/RISCV/RISCVSubtarget.h (+4)
• (modified) llvm/lib/Target/RISCV/RISCVTargetMachine.cpp (+2)
• (modified) llvm/test/CodeGen/RISCV/O3-pipeline.ll (+1-1)
• (modified) llvm/test/CodeGen/RISCV/macro-fusion-lui-addi.ll (+15)

diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
index 3d3486b7fa89563..548579173f0ede4 100644
--- a/llvm/lib/Target/RISCV/RISCVFeatures.td
+++ b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -902,6 +902,9 @@ def FeatureUnalignedVectorMem
                       "true", "Has reasonably performant unaligned vector "
                       "loads and stores">;
 
+def FeaturePostRAScheduler : SubtargetFeature<"use-postra-scheduler",
+    "UsePostRAScheduler", "true", "Schedule again after register allocation">;
+
 def TuneNoOptimizedZeroStrideLoad
    : SubtargetFeature<"no-optimized-zero-stride-load", "HasOptimizedZeroStrideLoad",
                       "false", "Hasn't optimized (perform fewer memory operations)"
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
index 027d32d54160793..6b915e61c136086 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -107,6 +107,10 @@ class RISCVSubtarget : public RISCVGenSubtargetInfo {
   }
   bool enableMachineScheduler() const override { return true; }
 
+  bool enablePostRAScheduler() const override {
+    return getSchedModel().PostRAScheduler || UsePostRAScheduler;
+  }
+
   Align getPrefFunctionAlignment() const {
     return Align(TuneInfo->PrefFunctionAlignment);
   }
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index 1281528ea511a4d..651d24bae57263d 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -248,6 +248,8 @@ class RISCVPassConfig : public TargetPassConfig {
 public:
   RISCVPassConfig(RISCVTargetMachine &TM, PassManagerBase &PM)
       : TargetPassConfig(TM, PM) {
+    if (TM.getOptLevel() != CodeGenOptLevel::None)
+      substitutePass(&PostRASchedulerID, &PostMachineSchedulerID);
     setEnableSinkAndFold(EnableSinkFold);
   }
 
diff --git a/llvm/test/CodeGen/RISCV/O3-pipeline.ll b/llvm/test/CodeGen/RISCV/O3-pipeline.ll
index 277951782ce5ccb..30b6e1e541394d0 100644
--- a/llvm/test/CodeGen/RISCV/O3-pipeline.ll
+++ b/llvm/test/CodeGen/RISCV/O3-pipeline.ll
@@ -159,7 +159,7 @@
 ; CHECK-NEXT:       Insert KCFI indirect call checks
 ; CHECK-NEXT:       MachineDominator Tree Construction
 ; CHECK-NEXT:       Machine Natural Loop Construction
-; CHECK-NEXT:       Post RA top-down list latency scheduler
+; CHECK-NEXT:       PostRA Machine Instruction Scheduler
 ; CHECK-NEXT:       Analyze Machine Code For Garbage Collection
 ; CHECK-NEXT:       Machine Block Frequency Analysis
 ; CHECK-NEXT:       MachinePostDominator Tree Construction
diff --git a/llvm/test/CodeGen/RISCV/macro-fusion-lui-addi.ll b/llvm/test/CodeGen/RISCV/macro-fusion-lui-addi.ll
index 7de0fd050d65867..498e6cf23ba3495 100644
--- a/llvm/test/CodeGen/RISCV/macro-fusion-lui-addi.ll
+++ b/llvm/test/CodeGen/RISCV/macro-fusion-lui-addi.ll
@@ -3,6 +3,8 @@
 ;RUN:   | FileCheck %s --check-prefix=NOFUSION
 ;RUN: llc < %s -mtriple=riscv64 -mattr=+f,+lui-addi-fusion -mcpu=sifive-u74 \
 ;RUN:   -target-abi=lp64f | FileCheck %s --check-prefix=FUSION
+;RUN: llc < %s -mtriple=riscv64 -mattr=+f,+lui-addi-fusion,+use-postra-scheduler -mcpu=sifive-u74 \
+;RUN:   -target-abi=lp64f | FileCheck %s --check-prefixes=FUSION-POSTRA
 
 @.str = private constant [4 x i8] c"%f\0A\00", align 1
 
@@ -20,6 +22,13 @@ define void @foo(i32 signext %0, i32 signext %1) {
 ; FUSION-NEXT:    lui a0, %hi(.L.str)
 ; FUSION-NEXT:    addi a0, a0, %lo(.L.str)
 ; FUSION-NEXT:    tail bar@plt
+;
+; FUSION-POSTRA-LABEL: foo:
+; FUSION-POSTRA:       # %bb.0:
+; FUSION-POSTRA-NEXT:    fcvt.s.w fa0, a1
+; FUSION-POSTRA-NEXT:    lui a0, %hi(.L.str)
+; FUSION-POSTRA-NEXT:    addi a0, a0, %lo(.L.str)
+; FUSION-POSTRA-NEXT:    tail bar@plt
   %3 = sitofp i32 %1 to float
   tail call void @bar(ptr @.str, float %3)
   ret void
@@ -40,5 +49,11 @@ define i32 @test_matint() {
 ; FUSION-NEXT:    lui a0, 1
 ; FUSION-NEXT:    addiw a0, a0, -2048
 ; FUSION-NEXT:    ret
+;
+; FUSION-POSTRA-LABEL: test_matint:
+; FUSION-POSTRA:       # %bb.0:
+; FUSION-POSTRA-NEXT:    lui a0, 1
+; FUSION-POSTRA-NEXT:    addiw a0, a0, -2048
+; FUSION-POSTRA-NEXT:    ret
   ret i32 2048
 }

[wangpc-pp]

Ping.

[topperc]

LGTM