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| author | Martin Sebor <msebor@redhat.com> | 2017-02-14 04:38:54 +0000 |
|---|---|---|
| committer | Martin Sebor <msebor@gcc.gnu.org> | 2017-02-13 21:38:54 -0700 |
| commit | ee75687bc64b31bb3561ba77d2660f90a1be4a75 (patch) | |
| tree | 36896367a96a517e5464186f833c9f6ee7a3df02 /gcc/gimple-ssa-sprintf.c | |
| parent | f2348577b2bfa7df6f6e8eb0ccc7865a6a6c9d09 (diff) | |
| download | gcc-ee75687bc64b31bb3561ba77d2660f90a1be4a75.tar.gz | |
PR middle-end/79496 - call to snprintf with zero size eliminated with -Wformat-truncation=2
gcc/ChangeLog:
PR middle-end/79496
* gimple-ssa-sprintf.c (pass_sprintf_length::handle_gimple_call): Avoid
clearing info.nowrite flag when snprintf size argument is a range.
gcc/testsuite/ChangeLog:
PR middle-end/79496
* gcc.dg/tree-ssa/builtin-snprintf-2.c: New test.
From-SVN: r245415
Diffstat (limited to 'gcc/gimple-ssa-sprintf.c')
| -rw-r--r-- | gcc/gimple-ssa-sprintf.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/gcc/gimple-ssa-sprintf.c b/gcc/gimple-ssa-sprintf.c index e6cc31d1c48..b2db8b848b0 100644 --- a/gcc/gimple-ssa-sprintf.c +++ b/gcc/gimple-ssa-sprintf.c @@ -3443,6 +3443,10 @@ pass_sprintf_length::handle_gimple_call (gimple_stmt_iterator *gsi) info.format = gimple_call_arg (info.callstmt, idx_format); + /* True when the destination size is constant as opposed to the lower + or upper bound of a range. */ + bool dstsize_cst_p = true; + if (idx_dstsize == HOST_WIDE_INT_M1U) { /* For non-bounded functions like sprintf, determine the size @@ -3483,8 +3487,8 @@ pass_sprintf_length::handle_gimple_call (gimple_stmt_iterator *gsi) else if (TREE_CODE (size) == SSA_NAME) { /* Try to determine the range of values of the argument - and use the greater of the two at -Wformat-level 1 and - the smaller of them at level 2. */ + and use the greater of the two at level 1 and the smaller + of them at level 2. */ wide_int min, max; enum value_range_type range_type = get_range_info (size, &min, &max); @@ -3495,6 +3499,11 @@ pass_sprintf_length::handle_gimple_call (gimple_stmt_iterator *gsi) ? wi::fits_uhwi_p (max) ? max.to_uhwi () : max.to_shwi () : wi::fits_uhwi_p (min) ? min.to_uhwi () : min.to_shwi ()); } + + /* The destination size is not constant. If the function is + bounded (e.g., snprintf) a lower bound of zero doesn't + necessarily imply it can be eliminated. */ + dstsize_cst_p = false; } } @@ -3511,7 +3520,7 @@ pass_sprintf_length::handle_gimple_call (gimple_stmt_iterator *gsi) without actually producing any. Pretend the size is unlimited in this case. */ info.objsize = HOST_WIDE_INT_MAX; - info.nowrite = true; + info.nowrite = dstsize_cst_p; } else { |