Add -vc-disable-indvars-opt option to control induction

variable optimization.

Add vc option for user to control induction variable optimization to
achieve better performance in some workload.

Author: kychendev

IGC/Options/include/igc/Options/VCApiOptions.td

@@ -83,6 +83,10 @@ def vc_disable_non_overlapping_region_opt :
   PlainFlag<"vc-disable-non-overlapping-region-opt">,
   HelpText<"Disable non-overlapping region optimization">;
 
+def vc_disable_indvars_opt :
+  PlainFlag<"vc-disable-indvars-opt">,
+  HelpText<"Disable induction variable optimization">;
+
 // Compatibility alias.
 def : PlainFlag<"doubleGRF">, Alias<large_GRF>,
   HelpText<"Alias for -ze-opt-large-register-file"> {

IGC/VectorCompiler/include/vc/Driver/Driver.h

@@ -108,6 +108,7 @@ struct CompileOptions {
   bool ForceLiveRangesLocalizationForAccUsage = false;
   bool ForceDisableNonOverlappingRegionOpt = false;
   bool IsLargeGRFMode = false;
+  bool ForceDisableIndvarsOpt = false;
 
   DisableLRCoalescingControl DisableLRCoalescingMode =
       DisableLRCoalescingControl::Default;

IGC/VectorCompiler/include/vc/Support/BackendConfig.h

@@ -109,6 +109,9 @@ struct GenXBackendOptions {
   // value in two-address operand)
   bool DisableNonOverlappingRegionOpt = false;
 
+  // Disable induction variable simplification
+  bool DisableIndvarsOpt = false;
+
   // use new Prolog/Epilog Insertion pass vs old CisaBuilder machinery
   bool UseNewStackBuilder = true;
 
@@ -309,6 +312,8 @@ class GenXBackendConfig : public ImmutablePass {
     return Options.DisableNonOverlappingRegionOpt;
   }
 
+  bool disableIndvarsOpt() const { return Options.DisableIndvarsOpt; }
+
   bool useNewStackBuilder() const { return Options.UseNewStackBuilder; }
 
   unsigned getStatelessPrivateMemSize() const {

IGC/VectorCompiler/lib/Driver/Driver.cpp

@@ -232,6 +232,8 @@ static GenXBackendOptions createBackendOptions(const vc::CompileOptions &Opts) {
     BackendOpts.LocalizeLRsForAccUsage = true;
   if (Opts.ForceDisableNonOverlappingRegionOpt)
     BackendOpts.DisableNonOverlappingRegionOpt = true;
+  if (Opts.ForceDisableIndvarsOpt)
+    BackendOpts.DisableIndvarsOpt = true;
   BackendOpts.FCtrl = Opts.FCtrl;
   BackendOpts.WATable = Opts.WATable;
   BackendOpts.IsLargeGRFMode = Opts.IsLargeGRFMode;
@@ -711,6 +713,8 @@ static Error fillApiOptions(const opt::ArgList &ApiOptions,
     Opts.SaveStackCallLinkage = true;
   if (ApiOptions.hasArg(OPT_vc_disable_non_overlapping_region_opt))
     Opts.ForceDisableNonOverlappingRegionOpt = true;
+  if (ApiOptions.hasArg(OPT_vc_disable_indvars_opt))
+    Opts.ForceDisableIndvarsOpt = true;
 
   if (opt::Arg *A =
           ApiOptions.getLastArg(OPT_enable_zebin_ze, OPT_disable_zebin_ze))

IGC/VectorCompiler/lib/GenXCodeGen/GenXTargetMachine.cpp

@@ -661,8 +661,12 @@ void GenXTargetMachine::adjustPassManager(PassManagerBuilder &PMBuilder) {
 
   // vldst.
   if (EmitVLoadStore) {
-    auto AddLowerLoadStore = [](const PassManagerBuilder &Builder,
+    auto AddLowerLoadStore = [this](const PassManagerBuilder &Builder,
                                 PassManagerBase &PM) {
+      GenXPassConfig *PassConfig = createGenXPassConfig(*this, PM);
+      vc::addPass(PM, PassConfig);
+      const GenXBackendConfig &BackendConfig = PassConfig->getBackendConfig();
+
       if (Builder.OptLevel > 0) {
         // Inline
         PM.add(createSROAPass());
@@ -681,7 +685,9 @@ void GenXTargetMachine::adjustPassManager(PassManagerBuilder &PMBuilder) {
         PM.add(createLoopRotatePass());
         PM.add(createLICMPass());
         PM.add(createInstructionCombiningPass());
-        PM.add(createIndVarSimplifyPass());
+        if (!(BackendConfig.disableIndvarsOpt())) {
+          PM.add(createIndVarSimplifyPass());
+        }
         PM.add(createLoopIdiomPass());
         PM.add(createLoopDeletionPass());
         PM.add(createSimpleLoopUnrollPass());

IGC/VectorCompiler/lib/Support/BackendConfig.cpp

@@ -88,6 +88,10 @@ static cl::opt<bool> DisableNonOverlappingRegionOptOpt(
     "vc-disable-non-overlapping-region-opt", cl::Hidden,
     cl::desc("Disable non-overlapping region optimization"));
 
+static cl::opt<bool> DisableIndvarsOptOpt(
+    "vc-disable-indvars-opt", cl::Hidden,
+    cl::desc("Disable induction variable optimization"));
+
 static cl::opt<bool>
     UseNewStackBuilderOpt("vc-use-new-stack-builder",
                           cl::desc("Use prolog/epilog insertion pass"));
@@ -173,6 +177,7 @@ void GenXBackendOptions::enforceLLVMOptions() {
   enforceOptionIfSpecified(DisableExtraCoalescing, DisableExtraCoalescingOpt);
   enforceOptionIfSpecified(DisableNonOverlappingRegionOpt,
                            DisableNonOverlappingRegionOptOpt);
+  enforceOptionIfSpecified(DisableIndvarsOpt, DisableIndvarsOptOpt);
   enforceOptionIfSpecified(FCtrl, FunctionControlOpt);
   enforceOptionIfSpecified(IsLargeGRFMode, LargeGRFModeOpt);
   enforceOptionIfSpecified(UseBindlessBuffers, UseBindlessBuffersOpt);