https://gcc.gnu.org/g:092dcef93d40ff3dfed6c35001325bf522785c25
commit r16-756-g092dcef93d40ff3dfed6c35001325bf522785c25
Author: Jakub Jelinek <ja...@redhat.com>
Date: Tue May 20 08:20:16 2025 +0200
libgcc: Small bitint_reduce_prec big-endian fixes
The big-endian _BitInt support in libgcc was written without any
testing and so I haven't discovered I've made one mistake in it
(in multiple places).
The bitint_reduce_prec function attempts to optimize inputs
which have some larger precision but at runtime they are found
to need smaller number of limbs.
For little-endian that is handled just by returning smaller
precision (or negative precision for signed), but for
big-endian we need to adjust the passed in limb pointer so that
when it returns smaller precision the argument still contains
the least significant limbs for the returned precision.
2025-05-20 Jakub Jelinek <ja...@redhat.com>
* libgcc2.c (bitint_reduce_prec): For big endian
__LIBGCC_BITINT_ORDER__ use ++*p and --*p instead of
++p and --p.
* soft-fp/bitint.h (bitint_reduce_prec): Likewise.
Diff:
---
libgcc/libgcc2.c | 10 +++++-----
libgcc/soft-fp/bitint.h | 10 +++++-----
2 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/libgcc/libgcc2.c b/libgcc/libgcc2.c
index 92cb79dc8f8d..faefff3730ca 100644
--- a/libgcc/libgcc2.c
+++ b/libgcc/libgcc2.c
@@ -1333,7 +1333,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec >= -1)
return -2;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -1347,7 +1347,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec >= -1)
return -2;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -1358,7 +1358,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if ((Wtype) mslimb >= 0)
{
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- --p;
+ --*p;
#endif
return prec - 1;
}
@@ -1387,7 +1387,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec == 0)
return 1;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -1400,7 +1400,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec == 0)
return 1;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
diff --git a/libgcc/soft-fp/bitint.h b/libgcc/soft-fp/bitint.h
index 07a7bcbb0b99..8d489e65a622 100644
--- a/libgcc/soft-fp/bitint.h
+++ b/libgcc/soft-fp/bitint.h
@@ -76,7 +76,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec >= -1)
return -2;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -90,7 +90,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec >= -1)
return -2;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -101,7 +101,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if ((BILtype) mslimb >= 0)
{
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- --p;
+ --*p;
#endif
return prec - 1;
}
@@ -130,7 +130,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec == 0)
return 1;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
@@ -143,7 +143,7 @@ bitint_reduce_prec (const UBILtype **p, SItype prec)
if (prec == 0)
return 1;
#if __LIBGCC_BITINT_ORDER__ == __ORDER_BIG_ENDIAN__
- ++p;
+ ++*p;
#else
--i;
#endif
