From 02c4de7631a177ea44149332aa1294a60ed9adad Mon Sep 17 00:00:00 2001 From: Martin Sebor Date: Mon, 28 Oct 2019 23:46:09 +0000 Subject: [PATCH] PR tree-optimization/92226 - live nul char store to array eliminated gcc/testsuite/ChangeLog: PR tree-optimization/92226 * gcc.dg/strlenopt-88.c: New test. gcc/ChangeLog: PR tree-optimization/92226 * tree-ssa-strlen.c (compare_nonzero_chars): Return -1 also when the offset is in the open range outlined by SI's length. From-SVN: r277545 --- gcc/ChangeLog | 6 ++ gcc/testsuite/ChangeLog | 5 + gcc/testsuite/gcc.dg/strlenopt-88.c | 196 ++++++++++++++++++++++++++++++++++++ gcc/tree-ssa-strlen.c | 19 +++- 4 files changed, 221 insertions(+), 5 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/strlenopt-88.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 9f35890..3f4f2dc 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,11 @@ 2019-10-28 Martin Sebor + PR tree-optimization/92226 + * tree-ssa-strlen.c (compare_nonzero_chars): Return -1 also when + the offset is in the open range outlined by SI's length. + +2019-10-28 Martin Sebor + PR c/66970 * doc/cpp.texi (__has_builtin): Document. * doc/extend.texi (__builtin_frob_return_addr): Correct spelling. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 1efdc30..8f9859f 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2019-10-28 Martin Sebor + PR tree-optimization/92226 + * gcc.dg/strlenopt-88.c: New test. + +2019-10-28 Martin Sebor + PR c/66970 * c-c++-common/cpp/has-builtin-2.c: New test. * c-c++-common/cpp/has-builtin-3.c: New test. diff --git a/gcc/testsuite/gcc.dg/strlenopt-88.c b/gcc/testsuite/gcc.dg/strlenopt-88.c new file mode 100644 index 0000000..cadd0de --- /dev/null +++ b/gcc/testsuite/gcc.dg/strlenopt-88.c @@ -0,0 +1,196 @@ +/* PR tree-optimization/92226 - live nul char store to array eliminated + { dg-do run } + { dg-options "-O2 -Wall" } */ + +#include "strlenopt.h" + +#define NOIPA __attribute__ ((noipa)) + +unsigned nfails; + +char a[8]; + +void test (int line, const char *func, size_t expect) +{ + size_t len = strlen (a); + if (len == expect) + return; + + ++nfails; + + __builtin_printf ("assertion failed in %s on line %i: " + "strlen (\"%s\") == %zu, got %zu\n", + func, line, a, expect, len); +} + +NOIPA const char* str (size_t n) +{ + return "9876543210" + 10 - n; +} + +#define T(name, CMPEXP, LEN, IDX, EXPECT) \ + NOIPA static void name (void) \ + { \ + const char *s = str (LEN); \ + if (strlen (s) CMPEXP) \ + { \ + strcpy (a, s); \ + a[IDX] = 0; \ + test (__LINE__, #name, EXPECT); \ + } \ + } typedef void dummy_type + + +T (len_eq_1_store_nul_0, == 1, 1, 0, 0); +T (len_eq_1_store_nul_1, == 1, 1, 1, 1); +T (len_eq_1_store_nul_2, == 1, 1, 2, 1); +T (len_eq_1_store_nul_3, == 1, 1, 3, 1); +T (len_eq_1_store_nul_4, == 1, 1, 4, 1); + +T (len_eq_2_store_nul_0, == 2, 2, 0, 0); +T (len_eq_2_store_nul_1, == 2, 2, 1, 1); +T (len_eq_2_store_nul_2, == 2, 2, 2, 2); +T (len_eq_2_store_nul_3, == 2, 2, 3, 2); +T (len_eq_2_store_nul_4, == 2, 2, 4, 2); + +T (len_eq_3_store_nul_0, == 3, 3, 0, 0); +T (len_eq_3_store_nul_1, == 3, 3, 1, 1); +T (len_eq_3_store_nul_2, == 3, 3, 2, 2); +T (len_eq_3_store_nul_3, == 3, 3, 3, 3); +T (len_eq_3_store_nul_4, == 3, 3, 4, 3); + + +T (len_gt_1_store_nul_0, > 2, 2, 0, 0); +T (len_gt_1_store_nul_1, > 2, 2, 1, 1); +T (len_gt_1_store_nul_2, > 2, 2, 2, 2); +T (len_gt_1_store_nul_3, > 2, 2, 3, 2); +T (len_gt_1_store_nul_4, > 2, 2, 4, 2); + +T (len_gt_2_store_nul_0, > 2, 3, 0, 0); +T (len_gt_2_store_nul_1, > 2, 3, 1, 1); +T (len_gt_2_store_nul_2, > 2, 3, 2, 2); +T (len_gt_2_store_nul_3, > 2, 3, 3, 3); +T (len_gt_2_store_nul_4, > 2, 3, 4, 3); + +T (len_gt_3_store_nul_0, > 2, 4, 0, 0); +T (len_gt_3_store_nul_1, > 2, 4, 1, 1); +T (len_gt_3_store_nul_2, > 2, 4, 2, 2); +T (len_gt_3_store_nul_3, > 2, 4, 3, 3); +T (len_gt_3_store_nul_4, > 2, 4, 4, 4); + + +T (len_1_lt_4_store_nul_0, < 4, 1, 0, 0); +T (len_1_lt_4_store_nul_1, < 4, 1, 1, 1); +T (len_1_lt_4_store_nul_2, < 4, 1, 2, 1); +T (len_1_lt_4_store_nul_3, < 4, 1, 3, 1); +T (len_1_lt_4_store_nul_4, < 4, 1, 4, 1); +T (len_1_lt_4_store_nul_5, < 4, 1, 5, 1); +T (len_1_lt_4_store_nul_6, < 4, 1, 6, 1); +T (len_1_lt_4_store_nul_7, < 4, 1, 7, 1); + +T (len_2_lt_4_store_nul_0, < 4, 2, 0, 0); +T (len_2_lt_4_store_nul_1, < 4, 2, 1, 1); +T (len_2_lt_4_store_nul_2, < 4, 2, 2, 2); +T (len_2_lt_4_store_nul_3, < 4, 2, 3, 2); +T (len_2_lt_4_store_nul_4, < 4, 2, 4, 2); +T (len_2_lt_4_store_nul_5, < 4, 2, 5, 2); +T (len_2_lt_4_store_nul_6, < 4, 2, 6, 2); +T (len_2_lt_4_store_nul_7, < 4, 2, 7, 2); + +T (len_3_lt_4_store_nul_0, < 4, 3, 0, 0); +T (len_3_lt_4_store_nul_1, < 4, 3, 1, 1); +T (len_3_lt_4_store_nul_2, < 4, 3, 2, 2); +T (len_3_lt_4_store_nul_3, < 4, 3, 3, 3); +T (len_3_lt_4_store_nul_4, < 4, 3, 4, 3); +T (len_3_lt_4_store_nul_5, < 4, 3, 5, 3); +T (len_3_lt_4_store_nul_6, < 4, 3, 6, 3); +T (len_3_lt_4_store_nul_7, < 4, 3, 7, 3); + +T (len_7_lt_8_store_nul_0, < 8, 7, 0, 0); +T (len_7_lt_8_store_nul_1, < 8, 7, 1, 1); +T (len_7_lt_8_store_nul_2, < 8, 7, 2, 2); +T (len_7_lt_8_store_nul_3, < 8, 7, 3, 3); +T (len_7_lt_8_store_nul_4, < 8, 7, 4, 4); +T (len_7_lt_8_store_nul_5, < 8, 7, 5, 5); +T (len_7_lt_8_store_nul_6, < 8, 7, 6, 6); +T (len_7_lt_8_store_nul_7, < 8, 7, 7, 7); + + +int main (void) +{ + len_eq_1_store_nul_0 (); + len_eq_1_store_nul_1 (); + len_eq_1_store_nul_2 (); + len_eq_1_store_nul_3 (); + len_eq_1_store_nul_4 (); + + len_eq_2_store_nul_0 (); + len_eq_2_store_nul_1 (); + len_eq_2_store_nul_2 (); + len_eq_2_store_nul_3 (); + len_eq_2_store_nul_4 (); + + len_eq_3_store_nul_0 (); + len_eq_3_store_nul_1 (); + len_eq_3_store_nul_2 (); + len_eq_3_store_nul_3 (); + len_eq_3_store_nul_4 (); + + + len_gt_1_store_nul_0 (); + len_gt_1_store_nul_1 (); + len_gt_1_store_nul_2 (); + len_gt_1_store_nul_3 (); + len_gt_1_store_nul_4 (); + + len_gt_2_store_nul_0 (); + len_gt_2_store_nul_1 (); + len_gt_2_store_nul_2 (); + len_gt_2_store_nul_3 (); + len_gt_2_store_nul_4 (); + + len_gt_3_store_nul_0 (); + len_gt_3_store_nul_1 (); + len_gt_3_store_nul_2 (); + len_gt_3_store_nul_3 (); + len_gt_3_store_nul_4 (); + + len_1_lt_4_store_nul_0 (); + len_1_lt_4_store_nul_1 (); + len_1_lt_4_store_nul_2 (); + len_1_lt_4_store_nul_3 (); + len_1_lt_4_store_nul_4 (); + len_1_lt_4_store_nul_5 (); + len_1_lt_4_store_nul_6 (); + len_1_lt_4_store_nul_7 (); + + len_2_lt_4_store_nul_0 (); + len_2_lt_4_store_nul_1 (); + len_2_lt_4_store_nul_2 (); + len_2_lt_4_store_nul_3 (); + len_2_lt_4_store_nul_4 (); + len_2_lt_4_store_nul_5 (); + len_2_lt_4_store_nul_6 (); + len_2_lt_4_store_nul_7 (); + + len_3_lt_4_store_nul_0 (); + len_3_lt_4_store_nul_1 (); + len_3_lt_4_store_nul_2 (); + len_3_lt_4_store_nul_3 (); + len_3_lt_4_store_nul_4 (); + len_3_lt_4_store_nul_5 (); + len_3_lt_4_store_nul_6 (); + len_3_lt_4_store_nul_7 (); + + len_7_lt_8_store_nul_0 (); + len_7_lt_8_store_nul_1 (); + len_7_lt_8_store_nul_2 (); + len_7_lt_8_store_nul_3 (); + len_7_lt_8_store_nul_4 (); + len_7_lt_8_store_nul_5 (); + len_7_lt_8_store_nul_6 (); + len_7_lt_8_store_nul_7 (); + + if (nfails) + abort (); +} diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index 4381458..476bcf6 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -193,10 +193,11 @@ static void handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *); * +1 if SI is known to start with more than OFF nonzero characters. - * 0 if SI is known to start with OFF nonzero characters, - but is not known to start with more. + * 0 if SI is known to start with exactly OFF nonzero characters. - * -1 if SI might not start with OFF nonzero characters. */ + * -1 if SI either does not start with OFF nonzero characters + or the relationship between the number of leading nonzero + characters in SI and OFF is unknown. */ static inline int compare_nonzero_chars (strinfo *si, unsigned HOST_WIDE_INT off) @@ -221,7 +222,7 @@ compare_nonzero_chars (strinfo *si, unsigned HOST_WIDE_INT off, if (TREE_CODE (si->nonzero_chars) == INTEGER_CST) return compare_tree_int (si->nonzero_chars, off); - if (TREE_CODE (si->nonzero_chars) != SSA_NAME) + if (!rvals || TREE_CODE (si->nonzero_chars) != SSA_NAME) return -1; const value_range *vr @@ -232,7 +233,15 @@ compare_nonzero_chars (strinfo *si, unsigned HOST_WIDE_INT off, if (rng != VR_RANGE || !range_int_cst_p (vr)) return -1; - return compare_tree_int (vr->min (), off); + /* If the offset is less than the minimum length or if the bounds + of the length range are equal return the result of the comparison + same as in the constant case. Otherwise return a conservative + result. */ + int cmpmin = compare_tree_int (vr->min (), off); + if (cmpmin > 0 || tree_int_cst_equal (vr->min (), vr->max ())) + return cmpmin; + + return -1; } /* Return true if SI is known to be a zero-length string. */ -- 2.7.4