[LoongArch] Add option for disable MI scheduling

[wangleiat]

This option directly affects the return value of
enableMachineScheduler().

[llvmbot]

@llvm/pr-subscribers-backend-loongarch

Author: wanglei (wangleiat)

Changes

This option directly affects the return value of
enableMachineScheduler().

---

Full diff: https://github.com/llvm/llvm-project/pull/163150.diff

2 Files Affected:

• (modified) llvm/lib/Target/LoongArch/LoongArchSubtarget.cpp (+10)
• (modified) llvm/lib/Target/LoongArch/LoongArchSubtarget.h (+1-1)

diff --git a/llvm/lib/Target/LoongArch/LoongArchSubtarget.cpp b/llvm/lib/Target/LoongArch/LoongArchSubtarget.cpp
index 3acbe4992273a..6463fbb6922f7 100644
--- a/llvm/lib/Target/LoongArch/LoongArchSubtarget.cpp
+++ b/llvm/lib/Target/LoongArch/LoongArchSubtarget.cpp
@@ -22,11 +22,21 @@ using namespace llvm;
 #define GET_SUBTARGETINFO_CTOR
 #include "LoongArchGenSubtargetInfo.inc"
 
+static cl::opt<bool>
+    DisableMISched("loongarch-disable-misched", cl::Hidden,
+                   cl::desc("Disable LoongArch MI Scheduling"));
+
 static cl::opt<bool> UseAA("loongarch-use-aa", cl::init(true),
                            cl::desc("Enable the use of AA during codegen."));
 
 void LoongArchSubtarget::anchor() {}
 
+bool LoongArchSubtarget::enableMachineScheduler() const {
+  if (DisableMISched.getNumOccurrences())
+    return !DisableMISched;
+  return true;
+}
+
 // Enable use of alias analysis during code generation (during MI scheduling,
 // DAGCombine, etc.).
 bool LoongArchSubtarget::useAA() const { return UseAA; }
diff --git a/llvm/lib/Target/LoongArch/LoongArchSubtarget.h b/llvm/lib/Target/LoongArch/LoongArchSubtarget.h
index 5e12bafebb0d5..10266e93ee5d6 100644
--- a/llvm/lib/Target/LoongArch/LoongArchSubtarget.h
+++ b/llvm/lib/Target/LoongArch/LoongArchSubtarget.h
@@ -104,7 +104,7 @@ class LoongArchSubtarget : public LoongArchGenSubtargetInfo {
   Align getPrefLoopAlignment() const { return PrefLoopAlignment; }
   unsigned getMaxBytesForAlignment() const { return MaxBytesForAlignment; }
   unsigned getMaxInterleaveFactor() const { return MaxInterleaveFactor; }
-  bool enableMachineScheduler() const override { return true; }
+  bool enableMachineScheduler() const override;
   bool useAA() const override;
 };
 } // end namespace llvm

[SixWeining]

Do we have some tests?