================
@@ -482,5 +482,35 @@ ParsedTargetAttr
RISCVTargetInfo::parseTargetAttr(StringRef Features) const {
Ret.Tune = AttrString;
}
}
+
+ StringRef MCPU = this->getTargetOpts().CPU;
+ StringRef MTune = this->getTargetOpts().TuneCPU;
+
+ // attr-cpu override march only if arch isn't present.
+ if (FoundArch) {
+ // If tune-cpu infer from CPU, then try to keep it.
+ // Otherwise, just use current tune option.
+ if (Ret.Tune.empty() && MTune.empty()) {
+ if (!Ret.CPU.empty())
+ Ret.Tune = Ret.CPU; // Keep attr-cpu in tune-cpu
+ else if (!MCPU.empty())
+ Ret.Tune = MCPU; // Keep mcpu in tune-cpu
+ }
+
+ // Reassign mcpu due to attr-arch=<Adding-Extension> need
+ // target-feature from mcpu/march.
+ // Use attr-cpu will affect target-feature.
+ Ret.CPU = MCPU;
+
+ // arch=<full-arch-string> need keep target feature clean,
+ // use the baseline cpu.
+ if (llvm::find(Ret.Features, "__RISCV_TargetAttrNeedOverride") !=
+ Ret.Features.end())
+ Ret.CPU =
----------------
topperc wrote:
`RISCVProcessorModel` defines names that can be used for -mcpu and -mtune.
`RISCVTuneProcessorModel` defines name that can only be used for -mtune. These
just associate scheduler models with strings. You need to look at C++ code to
see how -mcpu and -mtune are propagated.
This code gets the TuneCPU from the tune-cpu function attribute if present.
Otherwise its the same as the CPU. Where CPU either comes from the target-cpu
attribute or the TargetCPU in TargetMachine. There is no TuneCPU in
TargetMachine so it can only be set differently through the tune-cpu attribute.
```
const RISCVSubtarget *
RISCVTargetMachine::getSubtargetImpl(const Function &F) const {
Attribute CPUAttr = F.getFnAttribute("target-cpu");
Attribute TuneAttr = F.getFnAttribute("tune-cpu");
Attribute FSAttr = F.getFnAttribute("target-features");
std::string CPU =
CPUAttr.isValid() ? CPUAttr.getValueAsString().str() : TargetCPU;
std::string TuneCPU =
TuneAttr.isValid() ? TuneAttr.getValueAsString().str() : CPU;
```
The lookup function for the scheduler is here
```
void MCSubtargetInfo::InitMCProcessorInfo(StringRef CPU, StringRef TuneCPU,
StringRef FS) {
FeatureBits = getFeatures(CPU, TuneCPU, FS, ProcDesc, ProcFeatures);
FeatureString = std::string(FS);
if (!TuneCPU.empty())
CPUSchedModel = &getSchedModelForCPU(TuneCPU);
else
CPUSchedModel = &MCSchedModel::Default;
}
```
https://github.com/llvm/llvm-project/pull/75804
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