On Fri, May 1, 2020 at 12:37 PM Carl Eugen Hoyos <ceffm...@gmail.com> wrote:

> >
> > So ICC on Linux defines __GNUC__ >= 5 yet doesn't support these builtins?
>
> No, but yes, this is the effect.
>

Does this patch work instead on the ICC compiler? GCC 4.2+ have support for
__has_builtin() which shouldn't be masqueraded by the ICC.

- dale
From b52049eea61e602382684534c18fd1e301b13d46 Mon Sep 17 00:00:00 2001
From: Dale Curtis <dalecurtis@chromium.org>
Date: Fri, 1 May 2020 10:20:43 -0700
Subject: [PATCH] Use gcc/clang builtins for av_sat_(add|sub)_64_c if
 available.

Signed-off-by: Dale Curtis <dalecurtis@chromium.org>
---
 libavutil/common.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/libavutil/common.h b/libavutil/common.h
index 11907e5ba7..915e91f8f7 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -299,11 +299,16 @@ static av_always_inline int av_sat_dsub32_c(int a, int b)
  * @return sum with signed saturation
  */
 static av_always_inline int64_t av_sat_add64_c(int64_t a, int64_t b) {
+#if (AV_GCC_VERSION_AT_LEAST(5,0) && __has_builtin(__builtin_add_overflow)) || defined(__clang__)
+  int64_t tmp;
+  return !__builtin_add_overflow(a, b, &tmp) ? tmp : (tmp < 0 ? INT64_MAX : INT64_MIN);
+#else
   if (b >= 0 && a >= INT64_MAX - b)
     return INT64_MAX;
   if (b <= 0 && a <= INT64_MIN - b)
     return INT64_MIN;
   return a + b;
+#endif
 }
 
 /**
@@ -314,11 +319,16 @@ static av_always_inline int64_t av_sat_add64_c(int64_t a, int64_t b) {
  * @return difference with signed saturation
  */
 static av_always_inline int64_t av_sat_sub64_c(int64_t a, int64_t b) {
+#if (AV_GCC_VERSION_AT_LEAST(5,0) && __has_builtin(__builtin_sub_overflow)) || defined(__clang__)
+  int64_t tmp;
+  return !__builtin_sub_overflow(a, b, &tmp) ? tmp : (tmp < 0 ? INT64_MAX : INT64_MIN);
+#else
   if (b <= 0 && a >= INT64_MAX + b) {
     return INT64_MAX;
   if (b >= 0 && a <= INT64_MIN + b) {
     return INT64_MIN;
   return a - b;
+#endif
 }
 
 /**
-- 
2.24.1.windows.2

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