[PowerPC] Use RegisterClassInfo::getRegPressureSetLimit

[wangpc-pp]

RegisterClassInfo::getRegPressureSetLimit is a wrapper of
TargetRegisterInfo::getRegPressureSetLimit with some logics to
adjust the limit by removing reserved registers.

It seems that we shouldn't use TargetRegisterInfo::getRegPressureSetLimit
directly, just like the comment "This limit must be adjusted
dynamically for reserved registers" said.

Separate from #118787

[llvmbot]

@llvm/pr-subscribers-backend-powerpc

Author: Pengcheng Wang (wangpc-pp)

Changes

RegisterClassInfo::getRegPressureSetLimit is a wrapper of
TargetRegisterInfo::getRegPressureSetLimit with some logics to
adjust the limit by removing reserved registers.

It seems that we shouldn't use TargetRegisterInfo::getRegPressureSetLimit
directly, just like the comment "This limit must be adjusted
dynamically for reserved registers" said.

Separate from #118787

---

Full diff: https://github.com/llvm/llvm-project/pull/120383.diff

1 Files Affected:

• (modified) llvm/lib/Target/PowerPC/PPCInstrInfo.cpp (+2-2)

diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index 44f6db5061e21a..fa45a7fb7fabe6 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -643,8 +643,8 @@ bool PPCInstrInfo::shouldReduceRegisterPressure(
   };
 
   // For now we only care about float and double type fma.
-  unsigned VSSRCLimit = TRI->getRegPressureSetLimit(
-      *MBB->getParent(), PPC::RegisterPressureSets::VSSRC);
+  unsigned VSSRCLimit =
+      RegClassInfo->getRegPressureSetLimit(PPC::RegisterPressureSets::VSSRC);
 
   // Only reduce register pressure when pressure is high.
   return GetMBBPressure(MBB)[PPC::RegisterPressureSets::VSSRC] >

[ecnelises]

I think this is technically NFC (for VSSRC there's no actual adjustment), so the change looks fine

[lei137]

LGTM
thx.