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

[Phoebe Wang via cfe-commits]

================
@@ -256,6 +256,18 @@ class LLVM_LIBRARY_VISIBILITY X86TargetInfo : public TargetInfo {
       HasSizeMismatch = RegSize != 32;
       return true;
     }
+    if (RegName.contains("di")) {
+      if (getTargetOpts().FeatureMap.lookup("reserve-edi")) {
+        if (RegName == "edi") {
+          HasSizeMismatch = RegSize != 32;
+        } else if (RegName == "di") {
+          HasSizeMismatch = RegSize != 16;
+        } else if (RegName == "dil" || RegName == "dih") {
+          HasSizeMismatch = RegSize != 8;
----------------
phoebewang wrote:

32-bit cannot use `dil` and `dih`.

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