From 33f8c0a14da482bc7884e5f663615a3d7fd08cff Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Fri, 19 May 2017 15:30:54 +0000 Subject: [PATCH] re PR sanitizer/80800 (UBSAN: yet another false positive) PR sanitizer/80800 * fold-const.c (extract_muldiv_1) : Add TYPE_OVERFLOW_WRAPS checks. * c-c++-common/ubsan/pr80800.c: New test. * c-c++-common/Wduplicated-branches-1.c: Adjust an expression. From-SVN: r248291 --- gcc/ChangeLog | 6 ++++++ gcc/fold-const.c | 2 ++ gcc/testsuite/ChangeLog | 6 ++++++ .../c-c++-common/Wduplicated-branches-1.c | 2 +- gcc/testsuite/c-c++-common/ubsan/pr80800.c | 25 ++++++++++++++++++++++ 5 files changed, 40 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/c-c++-common/ubsan/pr80800.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index c40af47..00aa02c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2017-05-19 Marek Polacek + + PR sanitizer/80800 + * fold-const.c (extract_muldiv_1) : Add + TYPE_OVERFLOW_WRAPS checks. + 2017-05-19 Thomas Schwinge * tree-core.h (enum omp_clause_default_kind): Add diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 19aa722..736552c 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -6281,11 +6281,13 @@ extract_muldiv_1 (tree t, tree c, enum tree_code code, tree wide_type, new operation. Likewise for the RHS from a MULT_EXPR. Otherwise, do something only if the second operand is a constant. */ if (same_p + && TYPE_OVERFLOW_WRAPS (ctype) && (t1 = extract_muldiv (op0, c, code, wide_type, strict_overflow_p)) != 0) return fold_build2 (tcode, ctype, fold_convert (ctype, t1), fold_convert (ctype, op1)); else if (tcode == MULT_EXPR && code == MULT_EXPR + && TYPE_OVERFLOW_WRAPS (ctype) && (t1 = extract_muldiv (op1, c, code, wide_type, strict_overflow_p)) != 0) return fold_build2 (tcode, ctype, fold_convert (ctype, op0), diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e8e2df5..dafa034 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,9 @@ +2017-05-19 Marek Polacek + + PR sanitizer/80800 + * c-c++-common/ubsan/pr80800.c: New test. + * c-c++-common/Wduplicated-branches-1.c: Adjust an expression. + 2017-05-19 Thomas Schwinge * c-c++-common/goacc/default-1.c: Update. diff --git a/gcc/testsuite/c-c++-common/Wduplicated-branches-1.c b/gcc/testsuite/c-c++-common/Wduplicated-branches-1.c index c0b93fc..7c5062d 100644 --- a/gcc/testsuite/c-c++-common/Wduplicated-branches-1.c +++ b/gcc/testsuite/c-c++-common/Wduplicated-branches-1.c @@ -89,7 +89,7 @@ f (int i, int *p) if (i == 8) /* { dg-warning "this condition has identical branches" } */ return i * 8 * i * 8; else - return 8 * i * 8 * i; + return i * 8 * i * 8; if (i == 9) /* { dg-warning "this condition has identical branches" } */ diff --git a/gcc/testsuite/c-c++-common/ubsan/pr80800.c b/gcc/testsuite/c-c++-common/ubsan/pr80800.c new file mode 100644 index 0000000..992c136 --- /dev/null +++ b/gcc/testsuite/c-c++-common/ubsan/pr80800.c @@ -0,0 +1,25 @@ +/* PR sanitizer/80800 */ +/* { dg-do run } */ +/* { dg-options "-fsanitize=undefined -fsanitize-undefined-trap-on-error" } */ + +int n = 20000; +int z = 0; + +int +fn1 (void) +{ + return (n * 10000 * z) * 50; +} + +int +fn2 (void) +{ + return (10000 * n * z) * 50; +} + +int +main () +{ + fn1 (); + fn2 (); +} -- 2.7.4