prologue insertion pass should not update global state

It seems that there was some work left to be donerelated to SIMDCF and
prologue insertion code. Replaced silent update of the global state
with a warning and an option to emit fatal error.

Author: aparshin-intel

IGC/VectorCompiler/lib/GenXCodeGen/GenXPrologEpilogInsertion.cpp

@@ -82,9 +82,15 @@ static cl::opt<bool>
     ForceRetMemPassing("vc-stack-force-ret-mem",
                        cl::desc("Pass all stackcall retval via stackmem"),
                        cl::init(false));
-static cl::opt<bool> HandleMaskArgs("vc-stack-handle-mask-args",
+static cl::opt<bool>
+    DefaultMaskArgsProcessingPolicy("vc-stack-handle-mask-args",
                                     cl::desc("Pass i1 arguments of stackcalls"),
                                     cl::init(true));
+static cl::opt<bool>
+    AbortOnSIMDCF("vc-prologue-insertion-aborts-on-simdcf",
+                  cl::desc("fatal error is reported on simdcf detection by "
+                           "prologue insertion pass"),
+                  cl::init(false));
 
 namespace {
 
@@ -126,6 +132,7 @@ class GenXPrologEpilogInsertion
   unsigned ArgRegSize = 0;
   unsigned RetRegSize = 0;
 
+  bool HandleMaskArgs = true;
   bool UseGlobalMem = true;
 
   void generateKernelProlog(Function &F);
@@ -249,6 +256,7 @@ bool GenXPrologEpilogInsertion::runOnFunction(Function &F) {
   NumCalls = CallsCalculator().getNumCalls(F);
   UseGlobalMem =
       F.getParent()->getModuleFlag(ModuleMD::UseSVMStack) != nullptr;
+  HandleMaskArgs = DefaultMaskArgsProcessingPolicy;
   LLVM_DEBUG(dbgs() << "Visiting all calls in " << F.getName() << "\n");
   visit(F);
   LLVM_DEBUG(dbgs() << "Visiting finished\n");
@@ -273,13 +281,21 @@ void GenXPrologEpilogInsertion::visitCallInst(CallInst &I) {
     generateStackCall(&I);
   if (!IsIndirectCall) {
     auto IID = GenXIntrinsic::getAnyIntrinsicID(I.getCalledFunction());
-    if (IID == GenXIntrinsic::genx_alloca)
+    if (IID == GenXIntrinsic::genx_alloca) {
       generateAlloca(&I);
+      return;
+    }
     // TODO: conformance fails when we pass i1 args in presence of SIMDCF. Funny
     // thing is that ISPC doesn't use goto/join in its recursion tests so
     // they're fine (i.e. they're not affected by this option) unlike CM
-    else if (IID == GenXIntrinsic::genx_simdcf_goto)
+    if (IID == GenXIntrinsic::genx_simdcf_goto) {
       HandleMaskArgs = false;
+      DiagnosticInfoPrologEpilogInsertion DiagErr(
+          I.getFunction()->getName() + ": simdcf may not be properly supported",
+          AbortOnSIMDCF ? DS_Error : DS_Warning);
+      I.getContext().diagnose(DiagErr);
+      return;
+    }
   }
 }