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| author | Eric Botcazou <ebotcazou@libertysurf.fr> | 2006-09-10 23:27:36 +0200 |
|---|---|---|
| committer | Eric Botcazou <ebotcazou@gcc.gnu.org> | 2006-09-10 21:27:36 +0000 |
| commit | de097a3b99ba39804410a1a1c06412cd2dd9f1d1 (patch) | |
| tree | d3c5020c21152292317e1a64bd9a4574e3d04193 /gcc/combine.c | |
| parent | 4fe337f67a76d1b8288a3c63dec86dbaed77da4c (diff) | |
| download | gcc-de097a3b99ba39804410a1a1c06412cd2dd9f1d1.zip gcc-de097a3b99ba39804410a1a1c06412cd2dd9f1d1.tar.gz gcc-de097a3b99ba39804410a1a1c06412cd2dd9f1d1.tar.bz2 | |
re PR rtl-optimization/28636 (Miscompiled loop)
PR rtl-optimization/28636
* combine.c (force_to_mode): Test for side-effects before
substituting by zero.
(simplify_shift_const): Likewise for zero or other constants.
From-SVN: r116827
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 727e625..0f4ea02 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -6860,7 +6860,7 @@ force_to_mode (rtx x, enum machine_mode mode, unsigned HOST_WIDE_INT mask, nonzero = nonzero_bits (x, mode); /* If none of the bits in X are needed, return a zero. */ - if (! just_select && (nonzero & mask) == 0) + if (!just_select && (nonzero & mask) == 0 && !side_effects_p (x)) x = const0_rtx; /* If X is a CONST_INT, return a new one. Do this here since the @@ -8637,14 +8637,14 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode, == 0)) code = LSHIFTRT; - if (code == LSHIFTRT - && GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT - && !(nonzero_bits (varop, shift_mode) >> count)) - varop = const0_rtx; - if (code == ASHIFT - && GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT - && !((nonzero_bits (varop, shift_mode) << count) - & GET_MODE_MASK (shift_mode))) + if (((code == LSHIFTRT + && GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT + && !(nonzero_bits (varop, shift_mode) >> count)) + || (code == ASHIFT + && GET_MODE_BITSIZE (shift_mode) <= HOST_BITS_PER_WIDE_INT + && !((nonzero_bits (varop, shift_mode) << count) + & GET_MODE_MASK (shift_mode)))) + && !side_effects_p (varop)) varop = const0_rtx; switch (GET_CODE (varop)) @@ -9229,9 +9229,12 @@ simplify_shift_const_1 (enum rtx_code code, enum machine_mode result_mode, if (outer_op == AND) x = simplify_and_const_int (NULL_RTX, result_mode, x, outer_const); else if (outer_op == SET) - /* This means that we have determined that the result is - equivalent to a constant. This should be rare. */ - x = GEN_INT (outer_const); + { + /* This means that we have determined that the result is + equivalent to a constant. This should be rare. */ + if (!side_effects_p (x)) + x = GEN_INT (outer_const); + } else if (GET_RTX_CLASS (outer_op) == RTX_UNARY) x = simplify_gen_unary (outer_op, result_mode, x, result_mode); else |