[llvm] [RISCV] Correct the limit of RegPresureSet `GPRAll` (PR #118473)

[Matt Arsenault via llvm-commits]

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@@ -934,3 +934,17 @@ bool RISCVRegisterInfo::getRegAllocationHints(
 
   return BaseImplRetVal;
 }
+
+unsigned RISCVRegisterInfo::getRegPressureSetLimit(const MachineFunction &MF,
+                                                   unsigned Idx) const {
+  if (Idx == RISCV::RegisterPressureSets::GPRAll) {
+    unsigned Reserved = 0;
+    BitVector ReservedRegs = getReservedRegs(MF);
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arsenm wrote:

This should query the reserved registers from MachineRegisterInfo instead of doing a fresh computation of the set 

https://github.com/llvm/llvm-project/pull/118473