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| author | Jim Wilson <wilson@gcc.gnu.org> | 1996-12-16 18:25:39 -0800 |
|---|---|---|
| committer | Jim Wilson <wilson@gcc.gnu.org> | 1996-12-16 18:25:39 -0800 |
| commit | b3728b0e0e28b8cf7a3f4f2fe7bd85f21a722ad3 (patch) | |
| tree | 3af77f2397ce8badc67a08ed1914ea14589f82b9 /gcc | |
| parent | 7b1bcb4940fcbb05d359df63900e089120c3addb (diff) | |
| download | gcc-b3728b0e0e28b8cf7a3f4f2fe7bd85f21a722ad3.zip gcc-b3728b0e0e28b8cf7a3f4f2fe7bd85f21a722ad3.tar.gz gcc-b3728b0e0e28b8cf7a3f4f2fe7bd85f21a722ad3.tar.bz2 | |
(nonzero_bits): Ifdef out calls to num_sign_bit_copies.
Add dummy define/undef for num_sign_bit_copies.
From-SVN: r13314
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/combine.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index f4e0b97..57100b9 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -7072,6 +7072,13 @@ simplify_and_const_int (x, mode, varop, constop) return x; } +/* We let num_sign_bit_copies recur into nonzero_bits as that is useful. + We don't let nonzero_bits recur into num_sign_bit_copies, because that + is less useful. We can't allow both, because that results in exponential + run time recusion. There is a nullstone testcase that triggered + this. This macro avoids accidental uses of num_sign_bit_copies. */ +#define num_sign_bit_copies() + /* Given an expression, X, compute which bits in X can be non-zero. We don't care about bits outside of those defined in MODE. @@ -7246,18 +7253,26 @@ nonzero_bits (x, mode) break; case NEG: +#if 0 + /* Disabled to avoid exponential mutual recursion between nonzero_bits + and num_sign_bit_copies. */ if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) == GET_MODE_BITSIZE (GET_MODE (x))) nonzero = 1; +#endif if (GET_MODE_SIZE (GET_MODE (x)) < mode_width) nonzero |= (GET_MODE_MASK (mode) & ~ GET_MODE_MASK (GET_MODE (x))); break; case ABS: +#if 0 + /* Disabled to avoid exponential mutual recursion between nonzero_bits + and num_sign_bit_copies. */ if (num_sign_bit_copies (XEXP (x, 0), GET_MODE (x)) == GET_MODE_BITSIZE (GET_MODE (x))) nonzero = 1; +#endif break; case TRUNCATE: @@ -7456,6 +7471,9 @@ nonzero_bits (x, mode) return nonzero; } + +/* See the macro definition above. */ +#undef num_sign_bit_copies /* Return the number of bits at the high-order end of X that are known to be equal to the sign bit. X will be used in mode MODE; if MODE is |