[clang] [llvm] [X86] Support EGPR for inline assembly. (PR #92338)

[Nick Desaulniers via llvm-commits]

================
@@ -58016,15 +58035,27 @@ X86TargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
       break;
     case 'r':   // GENERAL_REGS
     case 'l':   // INDEX_REGS
+      if (Subtarget.useInlineAsmGPR32()) {
+        if (VT == MVT::i8 || VT == MVT::i1)
+          return std::make_pair(0U, &X86::GR8_NOREX2RegClass);
+        if (VT == MVT::i16)
+          return std::make_pair(0U, &X86::GR16_NOREX2RegClass);
+        if (VT == MVT::i32 || VT == MVT::f32 ||
+            (!VT.isVector() && !Subtarget.is64Bit()))
+          return std::make_pair(0U, &X86::GR32_NOREX2RegClass);
+        if (VT != MVT::f80 && !VT.isVector())
+          return std::make_pair(0U, &X86::GR64_NOREX2RegClass);
+        break;
+      }
       if (VT == MVT::i8 || VT == MVT::i1)
-        return std::make_pair(0U, &X86::GR8_NOREX2RegClass);
+        return std::make_pair(0U, &X86::GR8RegClass);
       if (VT == MVT::i16)
-        return std::make_pair(0U, &X86::GR16_NOREX2RegClass);
+        return std::make_pair(0U, &X86::GR16RegClass);
       if (VT == MVT::i32 || VT == MVT::f32 ||
           (!VT.isVector() && !Subtarget.is64Bit()))
-        return std::make_pair(0U, &X86::GR32_NOREX2RegClass);
+        return std::make_pair(0U, &X86::GR32RegClass);
       if (VT != MVT::f80 && !VT.isVector())
-        return std::make_pair(0U, &X86::GR64_NOREX2RegClass);
+        return std::make_pair(0U, &X86::GR64RegClass);
----------------
nickdesaulniers wrote:

Is it more concise to use ternary expressions here rather than duplicate so much logic?
```c++
      if (VT == MVT::i8 || VT == MVT::i1)
        return std::make_pair(0U, Subtarget.useInlineAsmGPR32() ? &X86::GR8_NOREX2RegClass : &X86::GR8RegClass);
      if (VT == MVT::i16)
        return std::make_pair(0U, Subtarget.useInlineAsmGPR32() ? &X86::GR16_NOREX2RegClass : &X86::GR16RegClass);
      if (VT == MVT::i32 || VT == MVT::f32 ||
          (!VT.isVector() && !Subtarget.is64Bit()))
        return std::make_pair(0U, Subtarget.useInlineAsmGPR32() ? &X86::GR32_NOREX2RegClass : &X86::GR32RegClass);
      if (VT != MVT::f80 && !VT.isVector())
        return std::make_pair(0U, Subtarget.useInlineAsmGPR32() ? &X86::GR64_NOREX2RegClass : &X86::GR64RegClass);
```

https://github.com/llvm/llvm-project/pull/92338