[llvm] [TableGen] Introduce a less aggressive suppression for HwMode Decoder… (PR #86060)

[Craig Topper via llvm-commits]

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@@ -2417,21 +2436,67 @@ static bool Check(DecodeStatus &Out, DecodeStatus In) {
 
 // Collect all HwModes referenced by the target for encoding purposes,
 // returning a vector of corresponding names.
-static void
-collectHwModesReferencedForEncodings(const CodeGenHwModes &HWM,
-                                     std::vector<StringRef> &Names) {
+static void collectHwModesReferencedForEncodings(
+    const CodeGenHwModes &HWM, std::vector<StringRef> &Names,
+    NamespacesHwModesMap &NamespacesWithHwModes) {
   SmallBitVector BV(HWM.getNumModeIds());
   for (const auto &MS : HWM.getHwModeSelects()) {
     for (const HwModeSelect::PairType &P : MS.second.Items) {
-      if (P.second->isSubClassOf("InstructionEncoding"))
+      if (P.second->isSubClassOf("InstructionEncoding")) {
+        std::string DecoderNamespace =
+            std::string(P.second->getValueAsString("DecoderNamespace"));
+        if (P.first == DefaultMode) {
+          NamespacesWithHwModes[DecoderNamespace][""] = 1;
+        } else {
+          NamespacesWithHwModes[DecoderNamespace][HWM.getMode(P.first).Name] =
+              1;
+        }
         BV.set(P.first);
+      }
     }
   }
   transform(BV.set_bits(), std::back_inserter(Names), [&HWM](const int &M) {
+    if (M == DefaultMode)
+      return StringRef("");
     return HWM.getModeName(M, /*IncludeDefault=*/true);
   });
 }
 
+static void
+handleHwModesUnrelatedEncodings(const CodeGenInstruction *Instr,
+                                const std::vector<StringRef> &HwModeNames,
+                                NamespacesHwModesMap &NamespacesWithHwModes,
+                                std::vector<EncodingAndInst> &GlobalEncodings) {
+  const Record *InstDef = Instr->TheDef;
+
+  switch (DecoderEmitterSuppressDuplicates) {
+  case SUPPRESSION_DISABLE: {
+    for (StringRef HwModeName : HwModeNames)
+      GlobalEncodings.emplace_back(InstDef, Instr, HwModeName);
+    break;
+  }
+  case SUPPRESSION_LEVEL1: {
+    std::string DecoderNamespace =
+        std::string(InstDef->getValueAsString("DecoderNamespace"));
+    for (StringRef HwModeName : HwModeNames) {
+      if (NamespacesWithHwModes.count(DecoderNamespace) > 0) {
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topperc wrote:

Can we do this map lookup outside the loop? It's independent of HwModeName

https://github.com/llvm/llvm-project/pull/86060