[llvm] [RISCV] Refactor X60 scheduling model helper classes. NFC. (PR #151572)

[Mikhail R. Gadelha via llvm-commits]

================
@@ -13,78 +13,108 @@
 //
 //===----------------------------------------------------------------------===//
 
-class SMX60IsWorstCaseMX<string mx, list<string> MxList> {
-  string LLMUL = LargestLMUL<MxList>.r;
-  bit c = !eq(mx, LLMUL);
-}
+//===----------------------------------------------------------------------===//
+// Helpers
+
+// Maps LMUL string to corresponding value from the Values array
+// LMUL values map to array indices as follows:
+//   MF8 -> Values[0], MF4 -> Values[1], MF2 -> Values[2], M1 -> Values[3],
+//   M2 -> Values[4], M4 -> Values[5], M8 -> Values[6]
+// Shorter lists are allowed, e.g., widening instructions don't work on M8
+class GetLMULValue<list<int> Values, string LMUL> {
+  int Index = !cond(
+    !eq(LMUL, "MF8"): 0,
+    !eq(LMUL, "MF4"): 1,
+    !eq(LMUL, "MF2"): 2,
+    !eq(LMUL, "M1"):  3,
+    !eq(LMUL, "M2"):  4,
+    !eq(LMUL, "M4"):  5,
+    !eq(LMUL, "M8"):  6,
+  );
 
-class SMX60IsWorstCaseMXSEW<string mx, int sew, list<string> MxList, bit isF = 0> {
-  string LLMUL = LargestLMUL<MxList>.r;
-  int SSEW = SmallestSEW<mx, isF>.r;
-  bit c = !and(!eq(mx, LLMUL), !eq(sew, SSEW));
+  assert !lt(Index, !size(Values)),
+    "Missing LMUL value for '" # LMUL # "'. " #
+    "Expected at least " # !add(Index, 1) # " elements, but got " #
+    !size(Values) # ".";
+
+  int c = Values[Index];
----------------
mikhailramalho wrote:

Do you mind if we keep it as is? It's short and used in other scheduling models as well, and while it's not immediately clear what it stands for, my guess is that it stands for computed value.

https://github.com/llvm/llvm-project/pull/151572