[LICM] Add allowspeculation pass options.

[fhahn]

Summary

This adds a new option to control AllowSpeculation added in D119965 when
using -passes=....

This allows reproducing #54023 using opt.

[aeubanks]

llvm/include/llvm/Transforms/Scalar/LICM.h

74

should also implement

void printPipeline(raw_ostream &OS,
                     function_ref<StringRef(StringRef)> MapClassName2PassName);

with a corresponding test in llvm/test/Other/new-pm-print-pipeline.ll

[fhahn]

Implement printPipeline and add test.

[fhahn]

llvm/include/llvm/Transforms/Scalar/LICM.h

74

Done, thanks!

[fhahn]

Thanks!

llvm/include/llvm/Transforms/Scalar/LICM.h

 
 class LPMUpdater;
 class Loop;
 class LoopNest;
 
 extern cl::opt<unsigned> SetLicmMssaOptCap;
 extern cl::opt<unsigned> SetLicmMssaNoAccForPromotionCap;
 
+struct LICMOptions {
+  unsigned MssaOptCap;
+  unsigned MssaNoAccForPromotionCap;
+  bool AllowSpeculation;
+
+  LICMOptions()
+      : MssaOptCap(SetLicmMssaOptCap),
+        MssaNoAccForPromotionCap(SetLicmMssaNoAccForPromotionCap),
+        AllowSpeculation(true) {}
+
+  LICMOptions(unsigned MssaOptCap, unsigned MssaNoAccForPromotionCap,
+              bool AllowSpeculation)
+      : MssaOptCap(MssaOptCap),
+        MssaNoAccForPromotionCap(MssaNoAccForPromotionCap),
+        AllowSpeculation(AllowSpeculation) {}
+};
+
 /// Performs Loop Invariant Code Motion Pass.
 class LICMPass : public PassInfoMixin<LICMPass> {
-  unsigned LicmMssaOptCap;
-  unsigned LicmMssaNoAccForPromotionCap;
-  bool LicmAllowSpeculation;
+  LICMOptions Opts;
 
 public:
-  LICMPass()
-      : LicmMssaOptCap(SetLicmMssaOptCap),
-        LicmMssaNoAccForPromotionCap(SetLicmMssaNoAccForPromotionCap),
-        LicmAllowSpeculation(true) {}
-  LICMPass(unsigned LicmMssaOptCap, unsigned LicmMssaNoAccForPromotionCap,
-           bool LicmAllowSpeculation)
-      : LicmMssaOptCap(LicmMssaOptCap),
-        LicmMssaNoAccForPromotionCap(LicmMssaNoAccForPromotionCap),
-        LicmAllowSpeculation(LicmAllowSpeculation) {}
+  LICMPass(unsigned MssaOptCap, unsigned MssaNoAccForPromotionCap,
+           bool AllowSpeculation)
+      : LICMPass(LICMOptions(MssaOptCap, MssaNoAccForPromotionCap,
+                             AllowSpeculation)) {}
+  LICMPass(LICMOptions Opts) : Opts(Opts) {}
+
   PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
                         LoopStandardAnalysisResults &AR, LPMUpdater &U);
 };
 
 /// Performs LoopNest Invariant Code Motion Pass.
 class LNICMPass : public PassInfoMixin<LNICMPass> {
-  unsigned LicmMssaOptCap;
-  unsigned LicmMssaNoAccForPromotionCap;
-  bool LicmAllowSpeculation;
+  LICMOptions Opts;
 
 public:
-  LNICMPass()
-      : LicmMssaOptCap(SetLicmMssaOptCap),
-        LicmMssaNoAccForPromotionCap(SetLicmMssaNoAccForPromotionCap),
-        LicmAllowSpeculation(true) {}
-  LNICMPass(unsigned LicmMssaOptCap, unsigned LicmMssaNoAccForPromotionCap,
-            bool LicmAllowSpeculation)
-      : LicmMssaOptCap(LicmMssaOptCap),
-        LicmMssaNoAccForPromotionCap(LicmMssaNoAccForPromotionCap),
-        LicmAllowSpeculation(LicmAllowSpeculation) {}
+  LNICMPass(unsigned MssaOptCap, unsigned MssaNoAccForPromotionCap,
+            bool AllowSpeculation)
+      : Opts(LICMOptions(MssaOptCap, MssaNoAccForPromotionCap,
+                         AllowSpeculation)) {}
+  LNICMPass() {}
+
   PreservedAnalyses run(LoopNest &L, LoopAnalysisManager &AM,
                         LoopStandardAnalysisResults &AR, LPMUpdater &U);
 };
 } // end namespace llvm
 
 #endif // LLVM_TRANSFORMS_SCALAR_LICM_H

llvm/lib/Passes/PassBuilder.cpp

if (ParamName == "nontrivial") {
           formatv("invalid LoopUnswitch pass parameter '{0}' ", ParamName)
               .str(),
           inconvertibleErrorCode());
     }
   }
   return Result;
 }
 
+Expected<LICMOptions> parseLICMOptions(StringRef Params) {
+  LICMOptions Result;
+  while (!Params.empty()) {
+    StringRef ParamName;
+    std::tie(ParamName, Params) = Params.split(';');
+
+    bool Enable = !ParamName.consume_front("no-");
+    if (ParamName == "allowspeculation") {
+      Result.AllowSpeculation = Enable;
+    } else {
+      return make_error<StringError>(
+          formatv("invalid LICM pass parameter '{0}' ", ParamName).str(),
+          inconvertibleErrorCode());
+    }
+  }
+  return Result;
+}
+
 Expected<bool> parseMergedLoadStoreMotionOptions(StringRef Params) {
   bool Result = false;
   while (!Params.empty()) {
     StringRef ParamName;
     std::tie(ParamName, Params) = Params.split(';');
 
     bool Enable = !ParamName.consume_front("no-");
     if (ParamName == "split-footer-bb") {

llvm/lib/Passes/PassRegistry.def

 #undef LOOP_ANALYSIS
 
 #ifndef LOOP_PASS
 #define LOOP_PASS(NAME, CREATE_PASS)
 #endif
 LOOP_PASS("canon-freeze", CanonicalizeFreezeInLoopsPass())
 LOOP_PASS("dot-ddg", DDGDotPrinterPass())
 LOOP_PASS("invalidate<all>", InvalidateAllAnalysesPass())
-LOOP_PASS("licm", LICMPass())
 LOOP_PASS("loop-idiom", LoopIdiomRecognizePass())
 LOOP_PASS("loop-instsimplify", LoopInstSimplifyPass())
 LOOP_PASS("loop-rotate", LoopRotatePass())
 LOOP_PASS("no-op-loop", NoOpLoopPass())
 LOOP_PASS("print", PrintLoopPass(dbgs()))
 LOOP_PASS("loop-deletion", LoopDeletionPass())
 LOOP_PASS("loop-simplifycfg", LoopSimplifyCFGPass())
 LOOP_PASS("loop-reduce", LoopStrengthReducePass())

 #endif
 LOOP_PASS_WITH_PARAMS("simple-loop-unswitch",
                       "SimpleLoopUnswitchPass",
                       [](std::pair<bool, bool> Params) {
                         return SimpleLoopUnswitchPass(Params.first, Params.second);
                       },
                       parseLoopUnswitchOptions,
                       "nontrivial;no-nontrivial;trivial;no-trivial")
+
+LOOP_PASS_WITH_PARAMS("licm", "LICMPass",
+                      [](LICMOptions Params) {
+                        return LICMPass(Params);
+                      },
+                      parseLICMOptions,
+                      "allowspeculation");
 #undef LOOP_PASS_WITH_PARAMS

llvm/lib/Transforms/Scalar/LICM.cpp

PreservedAnalyses LICMPass::run(Loop &L, LoopAnalysisManager &AM,
   if (!AR.MSSA)
     report_fatal_error("LICM requires MemorySSA (loop-mssa)");
 
   // For the new PM, we also can't use OptimizationRemarkEmitter as an analysis
   // pass.  Function analyses need to be preserved across loop transformations
   // but ORE cannot be preserved (see comment before the pass definition).
   OptimizationRemarkEmitter ORE(L.getHeader()->getParent());
 
-  LoopInvariantCodeMotion LICM(LicmMssaOptCap, LicmMssaNoAccForPromotionCap,
-                               LicmAllowSpeculation);
+  LoopInvariantCodeMotion LICM(Opts.MssaOptCap, Opts.MssaNoAccForPromotionCap,
+                               Opts.AllowSpeculation);
   if (!LICM.runOnLoop(&L, &AR.AA, &AR.LI, &AR.DT, AR.BFI, &AR.TLI, &AR.TTI,
                       &AR.SE, AR.MSSA, &ORE))
     return PreservedAnalyses::all();
 
   auto PA = getLoopPassPreservedAnalyses();
 
   PA.preserve<DominatorTreeAnalysis>();
   PA.preserve<LoopAnalysis>();
   PA.preserve<MemorySSAAnalysis>();
 
   return PA;
 }
 
 PreservedAnalyses LNICMPass::run(LoopNest &LN, LoopAnalysisManager &AM,
                                  LoopStandardAnalysisResults &AR,
                                  LPMUpdater &) {
   if (!AR.MSSA)
     report_fatal_error("LNICM requires MemorySSA (loop-mssa)");
 
   // For the new PM, we also can't use OptimizationRemarkEmitter as an analysis
   // pass.  Function analyses need to be preserved across loop transformations
   // but ORE cannot be preserved (see comment before the pass definition).
   OptimizationRemarkEmitter ORE(LN.getParent());
 
-  LoopInvariantCodeMotion LICM(LicmMssaOptCap, LicmMssaNoAccForPromotionCap,
-                               LicmAllowSpeculation);
+  LoopInvariantCodeMotion LICM(Opts.MssaOptCap, Opts.MssaNoAccForPromotionCap,
+                               Opts.AllowSpeculation);
 
   Loop &OutermostLoop = LN.getOutermostLoop();
   bool Changed = LICM.runOnLoop(&OutermostLoop, &AR.AA, &AR.LI, &AR.DT, AR.BFI,
                                 &AR.TLI, &AR.TTI, &AR.SE, AR.MSSA, &ORE, true);
 
   if (!Changed)
     return PreservedAnalyses::all();
 

llvm/test/Transforms/LICM/allow-speculation-option.ll

+; RUN: opt -passes='loop-mssa(licm<allowspeculation>)' -S %s | FileCheck --check-prefixes=COMMON,SPEC_ON %s
+; RUN: opt -passes='loop-mssa(licm<no-allowspeculation>)' -S %s | FileCheck --check-prefixes=COMMON,SPEC_OFF %s
+
+define void @test([10 x i32]* %ptr, i32 %N) {
+; COMMON-LABEL: @test(
+; COMMON-NEXT:  entry:
+; SPEC_ON-NEXT:   [[GEP:%.*]] = getelementptr [10 x i32], [10 x i32]* [[PTR:%.*]], i32 0, i32 0
+; COMMON-NEXT:    br label [[LOOP_HEADER:%.*]]
+; COMMON:       loop.header:
+; COMMON-NEXT:    [[IV:%.*]] = phi i32 [ 0, [[ENTRY:%.*]] ], [ [[IV_NEXT:%.*]], [[LOOP_LATCH:%.*]] ]
+; COMMON-NEXT:    [[CMP:%.*]] = icmp ult i32 [[IV]], [[N:%.*]]
+; COMMON-NEXT:    br i1 [[CMP]], label [[LOOP_LATCH]], label [[EXIT:%.*]]
+; COMMON:       loop.latch:
+; SPEC_OFF-NEXT:  [[GEP:%.*]] = getelementptr [10 x i32], [10 x i32]* [[PTR:%.*]], i32 0, i32 0
+; COMMON-NEXT:    [[GEP_IV:%.*]] = getelementptr i32, i32* [[GEP]], i32 [[IV]]
+; COMMON-NEXT:    store i32 9999, i32* [[GEP_IV]], align 4
+; COMMON-NEXT:    [[IV_NEXT]] = add i32 [[IV]], 1
+; COMMON-NEXT:    br label [[LOOP_HEADER]]
+; COMMON:       exit:
+; COMMON-NEXT:    ret void
+;
+entry:
+  br label %loop.header
+
+loop.header:
+  %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
+  %cmp = icmp ult i32 %iv, %N
+  br i1 %cmp, label %loop.latch, label %exit
+
+loop.latch:
+  %gep = getelementptr [10 x i32], [10 x i32]* %ptr, i32 0, i32 0
+  %gep.iv = getelementptr i32, i32* %gep, i32 %iv
+  store i32 9999, i32* %gep.iv
+  %iv.next = add i32 %iv, 1
+  br label %loop.header
+
+exit:
+  ret void
+}