[clang] [llvm] [X86] Support reserving EDI on x86-32 (PR #186123)

[Eli Friedman via cfe-commits]

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@@ -516,17 +516,23 @@ BitVector X86RegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   Reserved.set(X86::SSP);
 
   auto &ST = MF.getSubtarget<X86Subtarget>();
-  if (ST.is64Bit() && ST.hasUserReservedRegisters()) {
-    // Set r# as reserved register if user required
-    for (unsigned Reg = X86::R8; Reg <= X86::R15; ++Reg)
-      if (ST.isRegisterReservedByUser(Reg))
-        for (const MCPhysReg &SubReg : subregs_inclusive(Reg))
-          Reserved.set(SubReg);
-    if (ST.hasEGPR())
-      for (unsigned Reg = X86::R16; Reg <= X86::R31; ++Reg)
+  if (ST.hasUserReservedRegisters()) {
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efriedma-quic wrote:

I guess not directly related to your patch, but hasUserReservedRegisters() is a non-trivial function; should we cache the result in Subtarget?

https://github.com/llvm/llvm-project/pull/186123