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| author | Marek Polacek <polacek@redhat.com> | 2015-04-24 12:10:52 +0000 |
|---|---|---|
| committer | Marek Polacek <mpolacek@gcc.gnu.org> | 2015-04-24 12:10:52 +0000 |
| commit | 8c2b7f79721cb9ef50d996ef2073210e7402c69a (patch) | |
| tree | 109667391d09834474b25b70680f05eff7d00712 /gcc/c-family | |
| parent | 4853031ec832b9fd29e0894016038cc9f83e31cc (diff) | |
| download | gcc-8c2b7f79721cb9ef50d996ef2073210e7402c69a.zip gcc-8c2b7f79721cb9ef50d996ef2073210e7402c69a.tar.gz gcc-8c2b7f79721cb9ef50d996ef2073210e7402c69a.tar.bz2 | |
re PR c/63357 (Warn for P && P and P || P (same expression used multiple times in a condition))
PR c/63357
* c-common.c (warn_logical_operator): Warn if the operands have the
same expressions.
* doc/invoke.texi: Update description of -Wlogical-op.
* c-c++-common/Wlogical-op-1.c: New test.
From-SVN: r222408
Diffstat (limited to 'gcc/c-family')
| -rw-r--r-- | gcc/c-family/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/c-family/c-common.c | 39 |
2 files changed, 30 insertions, 13 deletions
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog index 718aa2a..1eb27cd 100644 --- a/gcc/c-family/ChangeLog +++ b/gcc/c-family/ChangeLog @@ -4,6 +4,10 @@ * c-common.c (c_fully_fold_internal): Use OPT_Wshift_count_negative and OPT_Wshift_count_overflow. + PR c/63357 + * c-common.c (warn_logical_operator): Warn if the operands have the + same expressions. + 2015-04-24 Marek Polacek <polacek@redhat.com> PR c/61534 diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c index b8e141e..9797e17 100644 --- a/gcc/c-family/c-common.c +++ b/gcc/c-family/c-common.c @@ -1781,22 +1781,35 @@ warn_logical_operator (location_t location, enum tree_code code, tree type, return; /* If both expressions have the same operand, if we can merge the - ranges, and if the range test is always false, then warn. */ + ranges, ... */ if (operand_equal_p (lhs, rhs, 0) && merge_ranges (&in_p, &low, &high, in0_p, low0, high0, - in1_p, low1, high1) - && 0 != (tem = build_range_check (UNKNOWN_LOCATION, - type, lhs, in_p, low, high)) - && integer_zerop (tem)) + in1_p, low1, high1)) { - if (or_op) - warning_at (location, OPT_Wlogical_op, - "logical %<or%> " - "of collectively exhaustive tests is always true"); - else - warning_at (location, OPT_Wlogical_op, - "logical %<and%> " - "of mutually exclusive tests is always false"); + tem = build_range_check (UNKNOWN_LOCATION, type, lhs, in_p, low, high); + /* ... and if the range test is always false, then warn. */ + if (tem && integer_zerop (tem)) + { + if (or_op) + warning_at (location, OPT_Wlogical_op, + "logical %<or%> of collectively exhaustive tests is " + "always true"); + else + warning_at (location, OPT_Wlogical_op, + "logical %<and%> of mutually exclusive tests is " + "always false"); + } + /* Or warn if the operands have exactly the same range, e.g. + A > 0 && A > 0. */ + else if (low0 == low1 && high0 == high1) + { + if (or_op) + warning_at (location, OPT_Wlogical_op, + "logical %<or%> of equal expressions"); + else + warning_at (location, OPT_Wlogical_op, + "logical %<and%> of equal expressions"); + } } } |