From 9c233ad0cb1b31ed305c3534e3d9279e5af43477 Mon Sep 17 00:00:00 2001 From: Martin Sebor Date: Fri, 18 Oct 2019 22:26:39 +0000 Subject: [PATCH] PR tree-optimization/92157 - incorrect strcmp() == 0 result for unknown strings gcc/testsuite/ChangeLog: PR tree-optimization/92157 * gcc.dg/strlenopt-69.c: Disable test failing due to PR 92155. * gcc.dg/strlenopt-87.c: New test. gcc/ChangeLog: PR tree-optimization/92157 * tree-ssa-strlen.c (handle_builtin_string_cmp): Be prepared for compute_string_length to return a negative result. From-SVN: r277194 --- gcc/ChangeLog | 6 ++ gcc/testsuite/ChangeLog | 6 ++ gcc/testsuite/gcc.dg/strlenopt-69.c | 3 + gcc/testsuite/gcc.dg/strlenopt-87.c | 105 ++++++++++++++++++++++++++++ gcc/tree-ssa-strlen.c | 12 +++- 5 files changed, 130 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/strlenopt-87.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6ef72d484a4..ccf870c2531 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2019-10-18 Martin Sebor + + PR tree-optimization/92157 + * tree-ssa-strlen.c (handle_builtin_string_cmp): Be prepared for + compute_string_length to return a negative result. + 2019-10-18 Richard Earnshaw * config/arm/arm.md (negv3): New expansion rule. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 58757027b9c..1a87247323e 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2019-10-18 Martin Sebor + + PR tree-optimization/92157 + * gcc.dg/strlenopt-69.c: Disable test failing due to PR 92155. + * gcc.dg/strlenopt-87.c: New test. + 2019-10-18 Richard Earnshaw * gcc.target/arm/negdi-3.c: Update expected output to allow NEGS. diff --git a/gcc/testsuite/gcc.dg/strlenopt-69.c b/gcc/testsuite/gcc.dg/strlenopt-69.c index 46ceb9ddb05..9ad8e2e8aac 100644 --- a/gcc/testsuite/gcc.dg/strlenopt-69.c +++ b/gcc/testsuite/gcc.dg/strlenopt-69.c @@ -66,11 +66,14 @@ void test_empty_string (void) b4[2] = '\0'; A (0 == strcmp (&a4[2], &b4[2])); +#if 0 + /* The following isn't handled yet due to PR 92155. */ clobber (a4, b4); memset (a4, 0, sizeof a4); memset (b4, 0, sizeof b4); A (0 == strcmp (a4, b4)); +#endif } /* Verify that comparison of dynamically created strings with unknown diff --git a/gcc/testsuite/gcc.dg/strlenopt-87.c b/gcc/testsuite/gcc.dg/strlenopt-87.c new file mode 100644 index 00000000000..082c7b2f734 --- /dev/null +++ b/gcc/testsuite/gcc.dg/strlenopt-87.c @@ -0,0 +1,105 @@ +/* PR tree-optimization/92157 - incorrect strcmp() == 0 result for unknown + strings​ + { dg-do run } + { dg-options "-O2 -Wall" } */ + +#include "strlenopt.h" + + +char a2[2], a3[3]; + + +static inline __attribute__ ((always_inline)) int +verify_not_equal (const char *s, const char *t, int x) +{ + int n = x < 0 ? strlen (s) : 0 < x ? strlen (t) : strlen (s) + strlen (t); + + if (strcmp (t, s) == 0) + abort (); + + return n; +} + +__attribute__ ((noipa)) int test_a2_s (const char *s) +{ + return verify_not_equal (a2, s, 0); +} + +__attribute__ ((noipa)) int test_a2_a3 (void) +{ + return verify_not_equal (a2, a3, 0); +} + +__attribute__ ((noipa)) int test_a3_a2 (void) +{ + return verify_not_equal (a3, a2, 0); +} + +__attribute__ ((noipa)) int test_s_a2 (const char *s) +{ + return verify_not_equal (s, a2, 0); +} + + +__attribute__ ((noipa)) int test_a2_s_1 (const char *s) +{ + return verify_not_equal (a2, s, -1); +} + +__attribute__ ((noipa)) int test_a2_a3_1 (void) +{ + return verify_not_equal (a2, a3, -1); +} + +__attribute__ ((noipa)) int test_a3_a2_1 (void) +{ + return verify_not_equal (a3, a2, -1); +} + +__attribute__ ((noipa)) int test_s_a2_1 (const char *s) +{ + return verify_not_equal (s, a2, -1); +} + + +__attribute__ ((noipa)) int test_a2_s_2 (const char *s) +{ + return verify_not_equal (a2, s, +1); +} + +__attribute__ ((noipa)) int test_a2_a3_2 (void) +{ + return verify_not_equal (a2, a3, +1); +} + +__attribute__ ((noipa)) int test_a3_a2_2 (void) +{ + return verify_not_equal (a3, a2, +1); +} + +__attribute__ ((noipa)) int test_s_a2_2 (const char *s) +{ + return verify_not_equal (s, a2, +1); +} + +int main (void) +{ + a2[0] = '1'; + a3[0] = '1'; + a3[0] = '2'; + + test_a2_s (""); + test_a2_a3 (); + test_a3_a2 (); + test_s_a2 (""); + + test_a2_s_1 (""); + test_a2_a3_1 (); + test_a3_a2_1 (); + test_s_a2_1 (""); + + test_a2_s_2 (""); + test_a2_a3_2 (); + test_a3_a2_2 (); + test_s_a2_2 (""); +} diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index d5833f69766..43814584a14 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -3842,7 +3842,7 @@ handle_builtin_string_cmp (gimple_stmt_iterator *gsi) HOST_WIDE_INT arysiz1 = -1, arysiz2 = -1; if (idx1) - cstlen1 = compute_string_length (idx1) + 1; + cstlen1 = compute_string_length (idx1); else arysiz1 = determine_min_objsize (arg1); @@ -3853,13 +3853,21 @@ handle_builtin_string_cmp (gimple_stmt_iterator *gsi) /* Repeat for the second argument. */ if (idx2) - cstlen2 = compute_string_length (idx2) + 1; + cstlen2 = compute_string_length (idx2); else arysiz2 = determine_min_objsize (arg2); if (cstlen2 < 0 && arysiz2 < 0) return false; + if (cstlen1 < 0 && cstlen2 < 0) + return false; + + if (cstlen1 >= 0) + ++cstlen1; + if (cstlen2 >= 0) + ++cstlen2; + /* The exact number of characters to compare. */ HOST_WIDE_INT cmpsiz = bound < 0 ? cstlen1 < 0 ? cstlen2 : cstlen1 : bound; /* The size of the array in which the unknown string is stored. */ -- 2.30.2