[llvm] [RISCV] Add groupid/bitmask for RISC-V extension (PR #94440)

[Craig Topper via llvm-commits]

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@@ -24,6 +24,14 @@ class Triple;
 
 namespace RISCV {
 
+namespace RISCVExtensionBitmaskTable {
+struct RISCVExtensionBitmask {
+  const char *Name;
+  unsigned GroupID;
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topperc wrote:

Can we use the bit position in the group instead of the mask here? It will make the structure more compact. There is currently a 4 byte gap between the group and the bit mask.

https://github.com/llvm/llvm-project/pull/94440