File ARM-Unaligned-access-fixes.patch of Package grpc.32570

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File ARM-Unaligned-access-fixes.patch of Package grpc.32570

From 316649c7bb8545571d9beb75dc2fb1abfbe6552f Mon Sep 17 00:00:00 2001
From: "easyaspi314 (Devin)" <easyaspi314@users.noreply.github.com>
Date: Tue, 7 Dec 2021 21:36:13 -0500
Subject: [PATCH] [ARM] Unaligned access fixes

- Use memcpy on ARMv6 and lower when unaligned access is supported
  - GCC has an internal conflict on whether unaligned access is available
    on ARMv6 so some parts do byteshift, some parts do not
  - aligned(1) is better on everything else
  - All this seems to be safe on even GCC 4.9.
 - Leave out the alignment check if unaligned access is supported on ARM.
---
 xxhash.h | 24 +++++++-----------------
 1 file changed, 7 insertions(+), 17 deletions(-)

diff --git a/xxhash.h b/xxhash.h
index 08ab794..4cf3f0d 100644
--- a/xxhash.h
+++ b/xxhash.h
@@ -1402,28 +1402,18 @@ XXH3_128bits_reset_withSecretandSeed(XXH3_state_t* statePtr,
  */
 
 #ifndef XXH_FORCE_MEMORY_ACCESS   /* can be defined externally, on command line for example */
-   /* prefer __packed__ structures (method 1) for gcc on armv7+ and mips */
-#  if !defined(__clang__) && \
-( \
-    (defined(__INTEL_COMPILER) && !defined(_WIN32)) || \
-    ( \
-        defined(__GNUC__) && ( \
-            (defined(__ARM_ARCH) && __ARM_ARCH >= 7) || \
-            ( \
-                defined(__mips__) && \
-                (__mips <= 5 || __mips_isa_rev < 6) && \
-                (!defined(__mips16) || defined(__mips_mips16e2)) \
-            ) \
-        ) \
-    ) \
-)
+   /* prefer __packed__ structures (method 1) for GCC
+    * < ARMv7 with unaligned access (e.g. Raspbian armhf) still uses byte shifting, so we use memcpy
+    * which for some reason does unaligned loads. */
+#  if defined(__GNUC__) && !(defined(__ARM_ARCH) && __ARM_ARCH < 7 && defined(__ARM_FEATURE_UNALIGNED))
 #    define XXH_FORCE_MEMORY_ACCESS 1
 #  endif
 #endif
 
 #ifndef XXH_FORCE_ALIGN_CHECK  /* can be defined externally */
-#  if defined(__i386)  || defined(__x86_64__) || defined(__aarch64__) \
-   || defined(_M_IX86) || defined(_M_X64)     || defined(_M_ARM64) /* visual */
+   /* don't check on x86, aarch64, or arm when unaligned access is available */
+#  if defined(__i386)  || defined(__x86_64__) || defined(__aarch64__) || defined(__ARM_FEATURE_UNALIGNED) \
+   || defined(_M_IX86) || defined(_M_X64)     || defined(_M_ARM64)    || defined(_M_ARM) /* visual */
 #    define XXH_FORCE_ALIGN_CHECK 0
 #  else
 #    define XXH_FORCE_ALIGN_CHECK 1
-- 
2.43.0

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