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| author | Richard Guenther <rguenther@suse.de> | 2007-03-11 16:08:35 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2007-03-11 16:08:35 +0000 |
| commit | 13338552e20fc9327a4bf620715939db13c23ba6 (patch) | |
| tree | 34d2d5d5c5a89386cd9edda2da8ff25f96630c53 /gcc/tree-vrp.c | |
| parent | d7419dec458b277eb34ed15a3895c166fc47f93b (diff) | |
| download | gcc-13338552e20fc9327a4bf620715939db13c23ba6.zip gcc-13338552e20fc9327a4bf620715939db13c23ba6.tar.gz gcc-13338552e20fc9327a4bf620715939db13c23ba6.tar.bz2 | |
re PR middle-end/31115 (libstdc++ 22_locale/num_get/get/char/2.cc 27_io/basic_ostream/inserters_arithmetic/char/6.cc)
2007-03-11 Richard Guenther <rguenther@suse.de>
PR tree-optimization/31115
* tree-vrp.c (extract_range_from_binary_expr): Make sure
the shift count is positive and non-anti-range for RSHIFT_EXPR.
A shift count of zero is not special as with *_DIV_EXPR.
(vrp_int_const_binop): Handle RSHIFT_EXPR for determining overflow
direction.
* gcc.dg/torture/pr31115.c: New testcase.
From-SVN: r122821
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index d3fd911..b137628 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -1569,6 +1569,12 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2) && (sgn1 >= 0 ? !is_positive_overflow_infinity (val2) : is_negative_overflow_infinity (val2))) + /* We only get in here with positive shift count, so the + overflow direction is the same as the sign of val1. + Actually rshift does not overflow at all, but we only + handle the case of shifting overflowed -INF and +INF. */ + || (code == RSHIFT_EXPR + && sgn1 >= 0) /* For division, the only case is -INF / -1 = +INF. */ || code == TRUNC_DIV_EXPR || code == FLOOR_DIV_EXPR @@ -1802,6 +1808,17 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr) return; } + /* If we have a RSHIFT_EXPR with a possibly negative shift + count or an anti-range shift count drop to VR_VARYING. + We currently cannot handle the overflow cases correctly. */ + if (code == RSHIFT_EXPR + && (vr1.type == VR_ANTI_RANGE + || !vrp_expr_computes_nonnegative (op1, &sop))) + { + set_value_range_to_varying (vr); + return; + } + /* Multiplications and divisions are a bit tricky to handle, depending on the mix of signs we have in the two ranges, we need to operate on different values to get the minimum and @@ -1816,7 +1833,8 @@ extract_range_from_binary_expr (value_range_t *vr, tree expr) the new range. */ /* Divisions by zero result in a VARYING value. */ - if (code != MULT_EXPR + if ((code != MULT_EXPR + && code != RSHIFT_EXPR) && (vr0.type == VR_ANTI_RANGE || range_includes_zero_p (&vr1))) { set_value_range_to_varying (vr); |