[llvm] RuntimeLibcalls: Describe register-returning divmod libcall ABIs (PR #217825)

[Peter Smith via llvm-commits]

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@@ -275,6 +275,63 @@ RuntimeLibcallsInfo::getFunctionTy(LLVMContext &Ctx, const Triple &TT,
                               false),
             Attrs};
   }
+  case RTLIB::impl___aeabi_idivmod:
+  case RTLIB::impl___aeabi_uidivmod:
+  case RTLIB::impl___aeabi_ldivmod:
+  case RTLIB::impl___aeabi_uldivmod:
+  case RTLIB::impl___rt_sdiv:
+  case RTLIB::impl___rt_udiv:
+  case RTLIB::impl___rt_sdiv64:
+  case RTLIB::impl___rt_udiv64: {
+    // The ARM AEABI (__aeabi_*divmod) and Windows (__rt_*div*) divmod functions
+    // return both values modeled as an inreg { iN, iN } struct (quotient,
+    // remainder). The __rt_*div* cases pass the arguments in opposite order.
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smithp35 wrote:



Could be worth removing the last sentence, or adding "but this does not affect the declaration."

https://github.com/llvm/llvm-project/pull/217825