[compiler-rt] [compiler-rt] Add big endian support to __aeabi_(idivmod|uidivmod|uldivmod) (PR #126277)

[Victor Campos via llvm-commits]

https://github.com/vhscampos created https://github.com/llvm/llvm-project/pull/126277

This patch makes these functions work in big endian mode:
 - `__aeabi_idivmod`.
 - `__aeabi_uidivmod`.

The `__aeabi_uldivmod` function was already compatible with big endian, but its test was not. So in this case, only the test needed fixing.

>From dd99a15df4556e310dde0966ccdcdbfce5b0ae9e Mon Sep 17 00:00:00 2001
From: Victor Campos <victor.campos at arm.com>
Date: Fri, 7 Feb 2025 17:35:59 +0000
Subject: [PATCH] [compiler-rt] Add big endian support to
 __aeabi_(idivmod|uidivmod|uldivmod)

This patch makes these functions work in big endian mode:
 - `__aeabi_idivmod`.
 - `__aeabi_uidivmod`.

The `__aeabi_uldivmod` function was already compatible with big endian,
but its test was not. So in this case, only the test needed fixing.
---
 compiler-rt/lib/builtins/arm/aeabi_idivmod.S       |  5 +++++
 compiler-rt/lib/builtins/arm/aeabi_uidivmod.S      |  5 +++++
 .../test/builtins/Unit/arm/aeabi_uldivmod_test.c   | 14 ++++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/compiler-rt/lib/builtins/arm/aeabi_idivmod.S b/compiler-rt/lib/builtins/arm/aeabi_idivmod.S
index bb80e4b96fc1aaa..b08f773e86483ab 100644
--- a/compiler-rt/lib/builtins/arm/aeabi_idivmod.S
+++ b/compiler-rt/lib/builtins/arm/aeabi_idivmod.S
@@ -40,7 +40,12 @@ DEFINE_COMPILERRT_FUNCTION(__aeabi_idivmod)
         mov     r1, r3
 #endif
         bl      SYMBOL_NAME(__divmodsi4)
+#if _YUGA_BIG_ENDIAN
+        mov     r1, r0
+        ldr     r0, [sp]
+#else
         ldr     r1, [sp]
+#endif
         add     sp, sp, #4
         pop     { pc }
 #endif //  defined(USE_THUMB_1)
diff --git a/compiler-rt/lib/builtins/arm/aeabi_uidivmod.S b/compiler-rt/lib/builtins/arm/aeabi_uidivmod.S
index df030769fd40bde..dc3cf90496c5979 100644
--- a/compiler-rt/lib/builtins/arm/aeabi_uidivmod.S
+++ b/compiler-rt/lib/builtins/arm/aeabi_uidivmod.S
@@ -47,7 +47,12 @@ LOCAL_LABEL(case_denom_larger):
         mov     r1, r3
 #endif
         bl      SYMBOL_NAME(__udivmodsi4)
+#if _YUGA_BIG_ENDIAN
+        mov     r1, r0
+        ldr     r0, [sp]
+#else
         ldr     r1, [sp]
+#endif
         add     sp, sp, #4
         pop     { pc }
 #endif
diff --git a/compiler-rt/test/builtins/Unit/arm/aeabi_uldivmod_test.c b/compiler-rt/test/builtins/Unit/arm/aeabi_uldivmod_test.c
index 2ff65a8b9ec3fa8..32b08d60484c755 100644
--- a/compiler-rt/test/builtins/Unit/arm/aeabi_uldivmod_test.c
+++ b/compiler-rt/test/builtins/Unit/arm/aeabi_uldivmod_test.c
@@ -13,15 +13,29 @@ int test_aeabi_uldivmod(du_int a, du_int b, du_int expected_q, du_int expected_r
 {
     du_int q, r;
     __asm__(
+#if _YUGA_BIG_ENDIAN
+        "movs r1, %Q[a] \n"
+        "movs r0, %R[a] \n"
+        "movs r3, %Q[b] \n"
+        "movs r2, %R[b] \n"
+#else
         "movs r0, %Q[a] \n"
         "movs r1, %R[a] \n"
         "movs r2, %Q[b] \n"
         "movs r3, %R[b] \n"
+#endif
         "bl __aeabi_uldivmod \n"
+#if _YUGA_BIG_ENDIAN
+        "movs %Q[q], r1\n"
+        "movs %R[q], r0\n"
+        "movs %Q[r], r3\n"
+        "movs %R[r], r2\n"
+#else
         "movs %Q[q], r0\n"
         "movs %R[q], r1\n"
         "movs %Q[r], r2\n"
         "movs %R[r], r3\n"
+#endif
         : [q] "=r" (q), [r] "=r"(r)
         : [a] "r"(a), [b] "r"(b)
         : "lr", "r0", "r1", "r2", "r3"