From 230a055501c52c9c78d7ed8b29ab553a10f234a4 Mon Sep 17 00:00:00 2001
From: James Zern <jzern@google.com>
Date: Tue, 3 Jun 2014 23:29:23 -0700
Subject: [PATCH] configure: set WEBP_HAVE_AVX2 when available

this is used to set WEBP_USE_AVX2 in files where the build flag won't be
used, i.e., dsp/enc.c, which enables VP8EncDspInitAVX2() to be called

Change-Id: I362f4ba39ca40d3e07a081292d5f743c649d9d7f
---
 configure.ac  |  5 +++++
 src/dsp/dsp.h |  6 +++++-
 src/dsp/enc.c | 11 ++++++-----
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/configure.ac b/configure.ac
index 0d6d0b85..1c5395ff 100644
--- a/configure.ac
+++ b/configure.ac
@@ -60,6 +60,11 @@ TEST_AND_ADD_CFLAGS([AM_CFLAGS], [-Wvla])
 AC_SUBST([AM_CFLAGS])
 
 TEST_AND_ADD_CFLAGS([AVX2_FLAGS], [-mavx2])
+# Assume the presence of any flag is enough. This could be made more robust
+# with a header and/or compile check if needed.
+AS_IF([test -n "$AVX2_FLAGS"], [
+  AC_DEFINE(WEBP_HAVE_AVX2, [1],
+            [Set to 1 if AVX2 is supported])])
 AC_SUBST([AVX2_FLAGS])
 
 dnl === CLEAR_LIBVARS([var_pfx])
diff --git a/src/dsp/dsp.h b/src/dsp/dsp.h
index 51c3bb8e..107bc5cc 100644
--- a/src/dsp/dsp.h
+++ b/src/dsp/dsp.h
@@ -14,6 +14,10 @@
 #ifndef WEBP_DSP_DSP_H_
 #define WEBP_DSP_DSP_H_
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include "../webp/types.h"
 
 #ifdef __cplusplus
@@ -40,7 +44,7 @@ extern "C" {
 #define WEBP_USE_SSE2
 #endif
 
-#if defined(__AVX2__)
+#if defined(__AVX2__) || defined(WEBP_HAVE_AVX2)
 #define WEBP_USE_AVX2
 #endif
 
diff --git a/src/dsp/enc.c b/src/dsp/enc.c
index d9b25904..e4ea8cb8 100644
--- a/src/dsp/enc.c
+++ b/src/dsp/enc.c
@@ -720,17 +720,18 @@ void VP8EncDspInit(void) {
     if (VP8GetCPUInfo(kSSE2)) {
       VP8EncDspInitSSE2();
     }
-    // TODO(jzern): this should be conditionally included based on a configure
-    // (HAVE_AVX2) define. We can't use WEBP_USE_AVX2/__AVX2__ here as -mavx2
-    // won't be defined for this file.
+#endif
+#if defined(WEBP_USE_AVX2)
     if (VP8GetCPUInfo(kAVX2)) {
       VP8EncDspInitAVX2();
     }
-#elif defined(WEBP_USE_NEON)
+#endif
+#if defined(WEBP_USE_NEON)
     if (VP8GetCPUInfo(kNEON)) {
       VP8EncDspInitNEON();
     }
-#elif defined(WEBP_USE_MIPS32)
+#endif
+#if defined(WEBP_USE_MIPS32)
     if (VP8GetCPUInfo(kMIPS32)) {
       VP8EncDspInitMIPS32();
     }