[llvm-mca] InstrBuilder: warnings for call/ret instructions are only reported once.

llvm-svn: 347514

Author: adibiagio

llvm/tools/llvm-mca/include/InstrBuilder.h

@@ -46,6 +46,9 @@ class InstrBuilder {
   DenseMap<unsigned short, std::unique_ptr<const InstrDesc>> Descriptors;
   DenseMap<const MCInst *, std::unique_ptr<const InstrDesc>> VariantDescriptors;
 
+  bool FirstCallInst;
+  bool FirstReturnInst;
+
   Expected<const InstrDesc &> createInstrDescImpl(const MCInst &MCI);
   Expected<const InstrDesc &> getOrCreateInstrDesc(const MCInst &MCI);
 
@@ -60,7 +63,11 @@ class InstrBuilder {
   InstrBuilder(const MCSubtargetInfo &STI, const MCInstrInfo &MCII,
                const MCRegisterInfo &RI, const MCInstrAnalysis &IA);
 
-  void clear() { VariantDescriptors.shrink_and_clear(); }
+  void clear() {
+    VariantDescriptors.shrink_and_clear();
+    FirstCallInst = true;
+    FirstReturnInst = true;
+  }
 
   Expected<std::unique_ptr<Instruction>> createInstruction(const MCInst &MCI);
 };

llvm/tools/llvm-mca/lib/InstrBuilder.cpp

@@ -29,7 +29,8 @@ InstrBuilder::InstrBuilder(const llvm::MCSubtargetInfo &sti,
                            const llvm::MCInstrInfo &mcii,
                            const llvm::MCRegisterInfo &mri,
                            const llvm::MCInstrAnalysis &mcia)
-    : STI(sti), MCII(mcii), MRI(mri), MCIA(mcia) {
+    : STI(sti), MCII(mcii), MRI(mri), MCIA(mcia), FirstCallInst(true),
+      FirstReturnInst(true) {
   computeProcResourceMasks(STI.getSchedModel(), ProcResourceMasks);
 }
 
@@ -455,17 +456,19 @@ InstrBuilder::createInstrDescImpl(const MCInst &MCI) {
   std::unique_ptr<InstrDesc> ID = llvm::make_unique<InstrDesc>();
   ID->NumMicroOps = SCDesc.NumMicroOps;
 
-  if (MCDesc.isCall()) {
+  if (MCDesc.isCall() && FirstCallInst) {
     // We don't correctly model calls.
     WithColor::warning() << "found a call in the input assembly sequence.\n";
     WithColor::note() << "call instructions are not correctly modeled. "
                       << "Assume a latency of 100cy.\n";
+    FirstCallInst = false;
   }
 
-  if (MCDesc.isReturn()) {
+  if (MCDesc.isReturn() && FirstReturnInst) {
     WithColor::warning() << "found a return instruction in the input"
                          << " assembly sequence.\n";
     WithColor::note() << "program counter updates are ignored.\n";
+    FirstReturnInst = false;
   }
 
   ID->MayLoad = MCDesc.mayLoad();