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[PATCH] PR 61876: Do not convert cast + __builtin_round into __builtin_lround unless -fno-math-errno is used
- From: Kyrill Tkachov <kyrylo dot tkachov at arm dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: 'Richard Biener' <richard dot guenther at gmail dot com>
- Date: Thu, 24 Jul 2014 13:36:41 +0100
- Subject: [PATCH] PR 61876: Do not convert cast + __builtin_round into __builtin_lround unless -fno-math-errno is used
- Authentication-results: sourceware.org; auth=none
Hi all,
This fixes PR 61876 by not converting the round + cast into an lround
unless -fno-math-errno is specified.
This is because lround can potentially set math errno whereas round +
cast doesn't, so the transformation isn't universally valid.
This will cause the tests:
gcc.target/aarch64/fcvt_double_long.c
gcc.target/aarch64/fcvt_double_ulong.c
to start passing on aarch64-linux.
aarch64 and x86 bootstrap and regtest looks fine.
Ok for trunk?
2014-06-23 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
PR middle-end/61876
* convert.c (convert_to_integer): Do not convert BUILT_IN_ROUND and
cast
when flat_errno_math is on.diff --git a/gcc/convert.c b/gcc/convert.c
index 09bc555..8dbf3cb 100644
--- a/gcc/convert.c
+++ b/gcc/convert.c
@@ -456,8 +456,8 @@ convert_to_integer (tree type, tree expr)
break;
CASE_FLT_FN (BUILT_IN_ROUND):
- /* Only convert in ISO C99 mode. */
- if (!targetm.libc_has_function (function_c99_misc))
+ /* Only convert in ISO C99 mode and with -fno-math-errno. */
+ if (!targetm.libc_has_function (function_c99_misc) || flag_errno_math)
break;
if (outprec < TYPE_PRECISION (integer_type_node)
|| (outprec == TYPE_PRECISION (integer_type_node)