[llvm] [TableGen] Use bitwise operations to access HwMode ID. (PR #88377)

[via llvm-commits]

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@@ -290,11 +290,55 @@ CodeEmitterGen::getInstructionCases(Record *R, CodeGenTarget &Target) {
     if (auto *DI = dyn_cast_or_null<DefInit>(RV->getValue())) {
       const CodeGenHwModes &HWM = Target.getHwModes();
       EncodingInfoByHwMode EBM(DI->getDef(), HWM);
+      unsigned EncodingHwModesInBits = DefaultMode;
+      for (auto &[ModeId, Encoding] : EBM) {
+        // DefaultMode is 0, skip it.
+        if (ModeId != DefaultMode)
+          EncodingHwModesInBits |= (1 << (ModeId - 1));
+      }
+
+      // Get HwModes for this Instr by bitwise AND operations,
+      // and find the table to which this instr and hwmode belong.
+      append("      unsigned HwMode = "
+             "STI.getHwMode(MCSubtargetInfo::HwMode_EncodingInfo);\n");
+      append("      HwMode &= " + itostr(EncodingHwModesInBits) + ";\n");
+      append("      switch (HwMode) {\n");
+      append("      default: llvm_unreachable(\"Unknown hardware mode!\"); "
+             "break;\n");
+      for (auto &[ModeId, Encoding] : EBM) {
+        if (ModeId == DefaultMode) {
+          append("      case " + itostr(DefaultMode) +
+                 ": InstBitsByHw = InstBits");
+        } else {
+          append("      case " + itostr(1 << (ModeId - 1)) +
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superZWT123 wrote:

Thank you very much, I believe this is currently the biggest issue. There is indeed a logical problem here that I will fix shortly. It’s due to changes I made to the interface, which resulted in mishandling the logic here. Thank you very much!

https://github.com/llvm/llvm-project/pull/88377