From d53b0a04a6a0f5048b37da2c14ac0cdabae5d348 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu.dantras@huawei.com>
Date: Wed, 20 Jan 2021 17:08:47 +0000
Subject: [PATCH] Fix ARM and AArch64 calling convention for passing small
 composite types

On big-endian the values need to be right-aligned within a 64-bit register, as if the value had been read with a 64-bit load instruction.
---
 compiler/rustc_target/src/abi/call/aarch64.rs | 24 ++-----------------
 compiler/rustc_target/src/abi/call/arm.rs     |  9 +------
 2 files changed, 3 insertions(+), 30 deletions(-)

diff --git a/compiler/rustc_target/src/abi/call/aarch64.rs b/compiler/rustc_target/src/abi/call/aarch64.rs
index 1ab7722edab..a5e985d4712 100644
--- a/compiler/rustc_target/src/abi/call/aarch64.rs
+++ b/compiler/rustc_target/src/abi/call/aarch64.rs
@@ -40,17 +40,7 @@ where
     let size = ret.layout.size;
     let bits = size.bits();
     if bits <= 128 {
-        let unit = if bits <= 8 {
-            Reg::i8()
-        } else if bits <= 16 {
-            Reg::i16()
-        } else if bits <= 32 {
-            Reg::i32()
-        } else {
-            Reg::i64()
-        };
-
-        ret.cast_to(Uniform { unit, total: size });
+        ret.cast_to(Uniform { unit: Reg::i64(), total: size });
         return;
     }
     ret.make_indirect();
@@ -72,17 +62,7 @@ where
     let size = arg.layout.size;
     let bits = size.bits();
     if bits <= 128 {
-        let unit = if bits <= 8 {
-            Reg::i8()
-        } else if bits <= 16 {
-            Reg::i16()
-        } else if bits <= 32 {
-            Reg::i32()
-        } else {
-            Reg::i64()
-        };
-
-        arg.cast_to(Uniform { unit, total: size });
+        arg.cast_to(Uniform { unit: Reg::i64(), total: size });
         return;
     }
     arg.make_indirect();
diff --git a/compiler/rustc_target/src/abi/call/arm.rs b/compiler/rustc_target/src/abi/call/arm.rs
index 26fed3bae4e..b560e11fe1c 100644
--- a/compiler/rustc_target/src/abi/call/arm.rs
+++ b/compiler/rustc_target/src/abi/call/arm.rs
@@ -45,14 +45,7 @@ where
     let size = ret.layout.size;
     let bits = size.bits();
     if bits <= 32 {
-        let unit = if bits <= 8 {
-            Reg::i8()
-        } else if bits <= 16 {
-            Reg::i16()
-        } else {
-            Reg::i32()
-        };
-        ret.cast_to(Uniform { unit, total: size });
+        ret.cast_to(Uniform { unit: Reg::i32(), total: size });
         return;
     }
     ret.make_indirect();