[llvm] [RISCV] Support isel for Zacas for 2*XLen types. (PR #77814)

[Yingwei Zheng via llvm-commits]

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@@ -754,8 +754,9 @@ bool RISCVRegisterInfo::getRegAllocationHints(
                         bool NeedGPRC) -> void {
     Register Reg = MO.getReg();
     Register PhysReg = Reg.isPhysical() ? Reg : Register(VRM->getPhys(Reg));
-    if (PhysReg && (!NeedGPRC || RISCV::GPRCRegClass.contains(PhysReg))) {
-      assert(!MO.getSubReg() && !VRRegMO.getSubReg() && "Unexpected subreg!");
+    // TODO: Add hints when there are GPRPair subregs?
+    if (PhysReg && (!NeedGPRC || RISCV::GPRCRegClass.contains(PhysReg)) &&
+        !MO.getSubReg() && !VRRegMO.getSubReg()) {
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dtcxzyw wrote:

I'd like to see test changes caused by this.

https://github.com/llvm/llvm-project/pull/77814