From 5fa908602fe0289d371626adf3f86406865e048a Mon Sep 17 00:00:00 2001
From: Andrei Alexeyev <akari@taisei-project.org>
Date: Sun, 8 Nov 2020 20:05:41 +0200
Subject: [PATCH] simd/x86: fix -Wcast-align warnings (gcc/clang)

This modifies glmm_{load,store}3 functions to make the compiler assume
the v pointer is appropriately aligned for the type it is being cast to.
Not tested with CGLM_ALL_UNALIGNED, but it probably doesn't matter.
---
 include/cglm/simd/x86.h |  4 ++--
 include/cglm/types.h    | 10 ++++++++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/include/cglm/simd/x86.h b/include/cglm/simd/x86.h
index 1360e20..d1d9cfd 100644
--- a/include/cglm/simd/x86.h
+++ b/include/cglm/simd/x86.h
@@ -175,7 +175,7 @@ glmm_load3(float v[3]) {
   __m128i xy;
   __m128  z;
 
-  xy = _mm_loadl_epi64((const __m128i *)v);
+  xy = _mm_loadl_epi64(CGLM_CASTPTR_ASSUME_ALIGNED(v, const __m128i));
   z  = _mm_load_ss(&v[2]);
 
   return _mm_movelh_ps(_mm_castsi128_ps(xy), z);
@@ -184,7 +184,7 @@ glmm_load3(float v[3]) {
 static inline
 void
 glmm_store3(float v[3], __m128 vx) {
-  _mm_storel_pi((__m64 *)&v[0], vx);
+  _mm_storel_pi(CGLM_CASTPTR_ASSUME_ALIGNED(v, __m64), vx);
   _mm_store_ss(&v[2], glmm_shuff1(vx, 2, 2, 2, 2));
 }
 
diff --git a/include/cglm/types.h b/include/cglm/types.h
index 60eb538..80463a2 100644
--- a/include/cglm/types.h
+++ b/include/cglm/types.h
@@ -32,6 +32,16 @@
 #  define CGLM_ALIGN_MAT CGLM_ALIGN(16)
 #endif
 
+#ifdef __GNUC__
+#  define CGLM_ASSUME_ALIGNED(expr, alignment) \
+  __builtin_assume_aligned((expr), (alignment))
+#else
+#  define CGLM_ASSUME_ALIGNED(expr, alignment) (expr)
+#endif
+
+#define CGLM_CASTPTR_ASSUME_ALIGNED(expr, type) \
+  ((type*)CGLM_ASSUME_ALIGNED((expr), __alignof__(type)))
+
 typedef float                   vec2[2];
 typedef float                   vec3[3];
 typedef int                    ivec3[3];