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https://github.com/crosstool-ng/crosstool-ng.git
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98 lines
2.9 KiB
Diff
98 lines
2.9 KiB
Diff
commit 5542236837c5c41435f8282ec92799f480c36f18
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Author: Paul Eggert <eggert@cs.ucla.edu>
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Date: Tue Jul 21 22:50:29 2015 -0700
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Port the 0x7efe...feff pattern to GCC 6.
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See Steve Ellcey's bug report in:
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https://sourceware.org/ml/libc-alpha/2015-07/msg00673.html
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* string/memrchr.c (MEMRCHR):
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* string/rawmemchr.c (RAWMEMCHR):
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* string/strchr.c (strchr):
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* string/strchrnul.c (STRCHRNUL):
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Rewrite code to avoid issues with signed shift overflow.
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---
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string/memrchr.c | 11 ++---------
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string/rawmemchr.c | 11 ++---------
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string/strchr.c | 9 ++-------
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string/strchrnul.c | 9 ++-------
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4 files changed, 8 insertions(+), 32 deletions(-)
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--- a/string/memrchr.c
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+++ b/string/memrchr.c
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@@ -96,15 +96,8 @@
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The 1-bits make sure that carries propagate to the next 0-bit.
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The 0-bits provide holes for carries to fall into. */
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-
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- if (sizeof (longword) != 4 && sizeof (longword) != 8)
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- abort ();
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-
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-#if LONG_MAX <= LONG_MAX_32_BITS
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- magic_bits = 0x7efefeff;
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-#else
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- magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff;
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-#endif
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+ magic_bits = -1;
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+ magic_bits = magic_bits / 0xff * 0xfe << 1 >> 1 | 1;
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/* Set up a longword, each of whose bytes is C. */
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charmask = c | (c << 8);
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--- a/string/rawmemchr.c
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+++ b/string/rawmemchr.c
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@@ -83,15 +83,8 @@
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The 1-bits make sure that carries propagate to the next 0-bit.
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The 0-bits provide holes for carries to fall into. */
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-
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- if (sizeof (longword) != 4 && sizeof (longword) != 8)
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- abort ();
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-
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-#if LONG_MAX <= LONG_MAX_32_BITS
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- magic_bits = 0x7efefeff;
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-#else
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- magic_bits = ((unsigned long int) 0x7efefefe << 32) | 0xfefefeff;
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-#endif
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+ magic_bits = -1;
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+ magic_bits = magic_bits / 0xff * 0xfe << 1 >> 1 | 1;
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/* Set up a longword, each of whose bytes is C. */
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charmask = c | (c << 8);
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--- a/string/strchr.c
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+++ b/string/strchr.c
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@@ -64,13 +64,8 @@
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The 1-bits make sure that carries propagate to the next 0-bit.
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The 0-bits provide holes for carries to fall into. */
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- switch (sizeof (longword))
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- {
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- case 4: magic_bits = 0x7efefeffL; break;
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- case 8: magic_bits = ((0x7efefefeL << 16) << 16) | 0xfefefeffL; break;
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- default:
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- abort ();
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- }
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+ magic_bits = -1;
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+ magic_bits = magic_bits / 0xff * 0xfe << 1 >> 1 | 1;
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/* Set up a longword, each of whose bytes is C. */
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charmask = c | (c << 8);
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--- a/string/strchrnul.c
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+++ b/string/strchrnul.c
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@@ -62,13 +62,8 @@
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The 1-bits make sure that carries propagate to the next 0-bit.
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The 0-bits provide holes for carries to fall into. */
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- switch (sizeof (longword))
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- {
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- case 4: magic_bits = 0x7efefeffL; break;
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- case 8: magic_bits = ((0x7efefefeL << 16) << 16) | 0xfefefeffL; break;
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- default:
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- abort ();
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- }
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+ magic_bits = -1;
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+ magic_bits = magic_bits / 0xff * 0xfe << 1 >> 1 | 1;
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/* Set up a longword, each of whose bytes is C. */
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charmask = c | (c << 8);
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