diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 976cf3a..64d4e41 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -363,7 +363,14 @@ lshift_double (l1, h1, count, prec, lv, hv, arith) count %= prec; #endif - if (count >= HOST_BITS_PER_WIDE_INT) + if (count >= 2 * HOST_BITS_PER_WIDE_INT) + { + /* Shifting by the host word size is undefined according to the + ANSI standard, so we must handle this as a special case. */ + *hv = 0; + *lv = 0; + } + else if (count >= HOST_BITS_PER_WIDE_INT) { *hv = (unsigned HOST_WIDE_INT) l1 << (count - HOST_BITS_PER_WIDE_INT); *lv = 0; @@ -398,7 +405,14 @@ rshift_double (l1, h1, count, prec, lv, hv, arith) count %= prec; #endif - if (count >= HOST_BITS_PER_WIDE_INT) + if (count >= 2 * HOST_BITS_PER_WIDE_INT) + { + /* Shifting by the host word size is undefined according to the + ANSI standard, so we must handle this as a special case. */ + *hv = signmask; + *lv = signmask; + } + else if (count >= HOST_BITS_PER_WIDE_INT) { *hv = signmask; *lv = ((signmask << (2 * HOST_BITS_PER_WIDE_INT - count - 1) << 1) |