[MCA] Use MCInstrAnalysis to analyse call/return instructions

[wangpc-pp]

The flag set in MCInstrDesc is not accurate and we should use
the result of MCInstrAnalysis.

[llvmbot]

@llvm/pr-subscribers-backend-systemz

@llvm/pr-subscribers-tools-llvm-mca

Author: Pengcheng Wang (wangpc-pp)

Changes

The flag set in MCInstrDesc is not accurate and we should use
the result of MCInstrAnalysis.

---

Full diff: https://github.com/llvm/llvm-project/pull/123882.diff

1 Files Affected:

• (modified) llvm/lib/MCA/InstrBuilder.cpp (+8-8)

diff --git a/llvm/lib/MCA/InstrBuilder.cpp b/llvm/lib/MCA/InstrBuilder.cpp
index 933ede71746e06..9304e6c57a3859 100644
--- a/llvm/lib/MCA/InstrBuilder.cpp
+++ b/llvm/lib/MCA/InstrBuilder.cpp
@@ -219,11 +219,10 @@ static void initializeUsedResources(InstrDesc &ID,
   });
 }
 
-static void computeMaxLatency(InstrDesc &ID, const MCInstrDesc &MCDesc,
-                              const MCSchedClassDesc &SCDesc,
-                              const MCSubtargetInfo &STI,
-                              unsigned CallLatency) {
-  if (MCDesc.isCall()) {
+static void computeMaxLatency(InstrDesc &ID, const MCSchedClassDesc &SCDesc,
+                              const MCSubtargetInfo &STI, unsigned CallLatency,
+                              bool IsCall) {
+  if (IsCall) {
     // We cannot estimate how long this call will take.
     // Artificially set an arbitrarily high latency.
     ID.MaxLatency = CallLatency;
@@ -599,7 +598,8 @@ InstrBuilder::createInstrDescImpl(const MCInst &MCI,
   ID->NumMicroOps = SCDesc.NumMicroOps;
   ID->SchedClassID = SchedClassID;
 
-  if (MCDesc.isCall() && FirstCallInst) {
+  bool IsCall = MCIA->isCall(MCI);
+  if (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. "
@@ -607,7 +607,7 @@ InstrBuilder::createInstrDescImpl(const MCInst &MCI,
     FirstCallInst = false;
   }
 
-  if (MCDesc.isReturn() && FirstReturnInst) {
+  if (MCIA->isReturn(MCI) && FirstReturnInst) {
     WithColor::warning() << "found a return instruction in the input"
                          << " assembly sequence.\n";
     WithColor::note() << "program counter updates are ignored.\n";
@@ -615,7 +615,7 @@ InstrBuilder::createInstrDescImpl(const MCInst &MCI,
   }
 
   initializeUsedResources(*ID, SCDesc, STI, ProcResourceMasks);
-  computeMaxLatency(*ID, MCDesc, SCDesc, STI, CallLatency);
+  computeMaxLatency(*ID, SCDesc, STI, CallLatency, IsCall);
 
   if (Error Err = verifyOperands(MCDesc, MCI))
     return std::move(Err);

[topperc]

Is this testable?

[wangpc-pp]

Is this testable?

Yes, I added a precommit test and you can see the second commit.

[topperc]

LGTM