[loop count assumptions] by default enable loop iteration assumption for AIE targets

Author: F-Stuckmann

clang/lib/Driver/ToolChains/AIE.cpp

@@ -184,6 +184,9 @@ void AIEToolChain::addClangTargetOptions(
 
   // Extend the max limit of the search depth in BasicAA
   CC1Args.append({"-mllvm", "-basic-aa-max-lookup-search-depth=10"});
+
+  // Enable Loop Iteration Count Assumptions
+  CC1Args.append({"-mllvm", "-enable-loop-iter-count-assumptions=true"});
 }
 
 // Avoid using newer dwarf versions, as the simulator doesn't understand newer

clang/test/CodeGen/aie/peel-itercount.c

@@ -14,8 +14,9 @@
 // and that the itercounts have been updated appropriately
 
 // CHECK-LABEL: loop28_37
-// CHECK: for.body.preheader:
-// CHECK: for.body.peel.next:
+// CHECK: for.body.peel.next6:
+// CHECK: for.cond.cleanup:
+// CHECK: for.body:
 // CHECK: !llvm.loop !6
 // CHECK: !6 = distinct !{!6, !7, !8, !9}
 // CHECK: !7 = !{!"llvm.loop.peeled.count", i32 2}

llvm/lib/Passes/PassBuilderPipelines.cpp

@@ -132,6 +132,7 @@
 #include "llvm/Transforms/Utils/CountVisits.h"
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
+#include "llvm/Transforms/Utils/LoopIterCountAssumptions.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
 #include "llvm/Transforms/Utils/MoveAutoInit.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
@@ -306,6 +307,11 @@ static cl::opt<bool> UseLoopVersioningLICM(
     "enable-loop-versioning-licm", cl::init(false), cl::Hidden,
     cl::desc("Enable the experimental Loop Versioning LICM pass"));
 
+static cl::opt<bool> EnableLoopIterCountToAssumptions(
+    "enable-loop-iter-count-assumptions", cl::Hidden, cl::init(false),
+    cl::desc(
+        "Enable Conversion of Loop Iteration Count Metadata to Assumptions."));
+
 namespace llvm {
 extern cl::opt<bool> EnableMemProfContextDisambiguation;
 
@@ -463,6 +469,9 @@ PassBuilder::buildO1FunctionSimplificationPipeline(OptimizationLevel Level,
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
                         /*AllowSpeculation=*/false));
 
+  if (EnableLoopIterCountToAssumptions)
+    LPM1.addPass(LoopIterCountAssumptions());
+
   LPM1.addPass(LoopRotatePass(/* Disable header duplication */ true,
                               isLTOPreLink(Phase)));
   // TODO: Investigate promotion cap for O1.
@@ -644,6 +653,9 @@ PassBuilder::buildFunctionSimplificationPipeline(OptimizationLevel Level,
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap,
                         /*AllowSpeculation=*/false));
 
+  if (EnableLoopIterCountToAssumptions)
+    LPM1.addPass(LoopIterCountAssumptions());
+
   // Disable header duplication in loop rotation at -Oz.
   LPM1.addPass(LoopRotatePass(EnableLoopHeaderDuplication ||
                                   Level != OptimizationLevel::Oz,