[PATCH] intprops: port to ICC 2021.1 Beta 20201112

[Paul Eggert]

* lib/intprops.h (_GL_HAS_BUILTIN_OVERFLOW_P):
Port to ICC 2021.1, which has a non-working __builtin_mul_overflow_p.
Add a clause for other compilers that claim to support
__builtin_mul_overflow_p, since we might as well find out about
slackers other than Clang and ICC.
(INT_MULTIPLY_WRAPV): ICC 2021 has GCC bug 91450, so treat it
like older GCCs even when it claims to be a newer one.
---
 ChangeLog      | 11 +++++++++++
 lib/intprops.h | 15 ++++++++++-----
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ae62fd779..c723356c1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2020-12-18  Paul Eggert  <eggert@cs.ucla.edu>
+
+       intprops: port to ICC 2021.1 Beta 20201112
+       * lib/intprops.h (_GL_HAS_BUILTIN_OVERFLOW_P):
+       Port to ICC 2021.1, which has a non-working __builtin_mul_overflow_p.
+       Add a clause for other compilers that claim to support
+       __builtin_mul_overflow_p, since we might as well find out about
+       slackers other than Clang and ICC.
+       (INT_MULTIPLY_WRAPV): ICC 2021 has GCC bug 91450, so treat it
+       like older GCCs even when it claims to be a newer one.
+
 2020-12-18  Bruno Haible  <bruno@clisp.org>
 
        intprops: Avoid potentially buggy __builtin_add_overflow in GCC 5, 6.
diff --git a/lib/intprops.h b/lib/intprops.h
index 2472962e6..52e60e5e2 100644
--- a/lib/intprops.h
+++ b/lib/intprops.h
@@ -246,10 +246,14 @@
 
 /* True if __builtin_add_overflow_p (A, B, C) works, and similarly for
    __builtin_sub_overflow_p and __builtin_mul_overflow_p.  */
-#ifdef __clang__
-/* Clang 9 lacks __builtin_mul_overflow_p, and even if it did it would
-   presumably run afoul of Clang bug 16404.  */
+#if defined __clang__ || defined __ICC
+/* Clang 11 lacks __builtin_mul_overflow_p, and even if it did it
+   would presumably run afoul of Clang bug 16404.  ICC 2021.1's
+   __builtin_add_overflow_p etc. are not treated as integral constant
+   expressions even when all arguments are.  */
 # define _GL_HAS_BUILTIN_OVERFLOW_P 0
+#elif defined __has_builtin
+# define _GL_HAS_BUILTIN_OVERFLOW_P __has_builtin (__builtin_mul_overflow_p)
 #else
 # define _GL_HAS_BUILTIN_OVERFLOW_P (7 <= __GNUC__)
 #endif
@@ -385,8 +389,9 @@
    _GL_INT_OP_WRAPV (a, b, r, -, _GL_INT_SUBTRACT_RANGE_OVERFLOW)
 #endif
 #if _GL_HAS_BUILTIN_MUL_OVERFLOW
-# if (9 < __GNUC__ + (3 <= __GNUC_MINOR__) \
-      || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__))
+# if ((9 < __GNUC__ + (3 <= __GNUC_MINOR__) \
+       || (__GNUC__ == 8 && 4 <= __GNUC_MINOR__)) \
+      && !defined __ICC)
 #  define INT_MULTIPLY_WRAPV(a, b, r) __builtin_mul_overflow (a, b, r)
 # else
    /* Work around GCC bug 91450.  */
-- 
2.27.0