[llvm] [RISCV][CFI] Emit cfi_offset for every callee-saved vector registers (PR #100455)

[Craig Topper via llvm-commits]

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@@ -53,6 +53,35 @@ static const std::pair<MCPhysReg, int8_t> FixedCSRFIMap[] = {
     {/*s9*/ RISCV::X25, -11}, {/*s10*/ RISCV::X26, -12},
     {/*s11*/ RISCV::X27, -13}};
 
+// This function returns {Base VReg, corresponding LMUL} of callee-saved VReg.
+// For example:
+// V2M2 -> {RISCV::V2, 2}
+// V8   -> {RISCV::V8, 1}
+static std::pair<MCPhysReg, int8_t> getCSBaseVRegLMULPair(MCPhysReg VR) {
+  assert(((VR >= RISCV::V1 && VR <= RISCV::V7) ||
+          (VR >= RISCV::V24 && VR <= RISCV::V31) ||
+          (VR >= RISCV::V2M2 && VR <= RISCV::V6M2) ||
+          (VR >= RISCV::V24M2 && VR <= RISCV::V30M2)) &&
+         "Invalid VR");
+
+  static constexpr std::pair<MCPhysReg, int8_t> VRegLMULLUT[] = {
+      {/*V2M2*/ RISCV::V2, 2},   {/*V4M2*/ RISCV::V4, 2},
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topperc wrote:

This needs static_asserts to make sure the registers are really in this order.

https://github.com/llvm/llvm-project/pull/100455