>From 991c85087796af881057deffa85c0c8e99d76167 Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Tue, 27 Aug 2019 04:23:44 -0700
Subject: [PATCH] Speed up INT_MULTIPLY_WRAPV on macOS
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Assume that __builtin_mul_overflow works OK with Clang on macOS.
Mattias Engdegård says it’s safe to assume the relevant library
is always available there.
* lib/intprops.h (_GL_HAS___builtin_mul_overflow):
New temporary internal macro.
(_GL_HAS_BUILTIN_MUL_OVERFLOW):
No need to work around the Clang bug on macOS.
---
 ChangeLog      | 11 +++++++++++
 lib/intprops.h | 13 ++++++++-----
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index e6f5a096a..9976e1833 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2019-08-27  Paul Eggert  <address@hidden>
+
+	Speed up INT_MULTIPLY_WRAPV on macOS
+	Assume that __builtin_mul_overflow works OK with Clang on macOS.
+	Mattias Engdegård says it’s safe to assume the relevant library
+	is always available there.
+	* lib/intprops.h (_GL_HAS___builtin_mul_overflow):
+	New temporary internal macro.
+	(_GL_HAS_BUILTIN_MUL_OVERFLOW):
+	No need to work around the Clang bug on macOS.
+
 2019-08-25  Paul Eggert  <address@hidden>
 
 	intprops.h, verify.h: port better to clang
diff --git a/lib/intprops.h b/lib/intprops.h
index ffd737028..2cb6ada51 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -31,6 +31,7 @@
 # else
 #  define _GL_HAS___builtin_add_overflow 0
 # endif
+# define _GL_HAS___builtin_mul_overflow _GL_HAS___builtin_add_overflow
 # define _GL_TEMPDEF___has_builtin
 #endif
 
@@ -240,12 +241,13 @@
 # define _GL_HAS_BUILTIN_ADD_OVERFLOW 0
 #endif
 
-/* True if __builtin_mul_overflow (A, B, P) works when P is non-null.  */
-#ifdef __clang__
-/* Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>.  */
-# define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
+/* True if __builtin_mul_overflow (A, B, P) works when P is non-null.
+   Work around Clang bug <https://bugs.llvm.org/show_bug.cgi?id=16404>.  */
+#if (__has_builtin (__builtin_mul_overflow) \
+     && (!defined __clang__ || (defined __APPLE__ && defined __MACH__)))
+# define _GL_HAS_BUILTIN_MUL_OVERFLOW 1
 #else
-# define _GL_HAS_BUILTIN_MUL_OVERFLOW _GL_HAS_BUILTIN_ADD_OVERFLOW
+# define _GL_HAS_BUILTIN_MUL_OVERFLOW 0
 #endif
 
 /* True if __builtin_add_overflow_p (A, B, C) works, and similarly for
@@ -589,6 +591,7 @@
 #ifdef _GL_TEMPDEF___has_builtin
 # undef __has_builtin
 # undef _GL_HAS___builtin_add_overflow
+# undef _GL_HAS___builtin_mul_overflow
 # undef _GL_TEMPDEF___has_builtin
 #endif
 
-- 
2.17.1