From 34599780d0de72faf5719ea08d11a061722b9d19 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 20 Jan 2021 08:48:34 +0100 Subject: [PATCH] tree-optimization/98758 - fix integer arithmetic in data-ref analysis This fixes some int arithmetic issues and a bogus truncation. 2021-01-20 Richard Biener PR tree-optimization/98758 * tree-data-ref.c (int_divides_p): Use lambda_int arguments. (lambda_matrix_right_hermite): Avoid undefinedness with signed integer abs and multiplication. (analyze_subscript_affine_affine): Use lambda_int. * gcc.dg/torture/pr98758.c: New testcase. --- gcc/testsuite/gcc.dg/torture/pr98758.c | 13 +++++++++++++ gcc/tree-data-ref.c | 12 ++++++------ 2 files changed, 19 insertions(+), 6 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr98758.c diff --git a/gcc/testsuite/gcc.dg/torture/pr98758.c b/gcc/testsuite/gcc.dg/torture/pr98758.c new file mode 100644 index 00000000000..7b9fdb2b613 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr98758.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ + +long *a, *b; +long c; +void d(void) +{ + b = a; + while (c) { + *a = (__INTPTR_TYPE__)(a += (long)1 << (sizeof(long) * 8 - 10)); + c = b[0]; + b = a; + } +} diff --git a/gcc/tree-data-ref.c b/gcc/tree-data-ref.c index 65fe6d5da91..9d07b415e9d 100644 --- a/gcc/tree-data-ref.c +++ b/gcc/tree-data-ref.c @@ -143,7 +143,7 @@ tree_fold_divides_p (const_tree a, const_tree b) /* Returns true iff A divides B. */ static inline bool -int_divides_p (int a, int b) +int_divides_p (lambda_int a, lambda_int b) { return ((b % a) == 0); } @@ -4280,10 +4280,10 @@ lambda_matrix_right_hermite (lambda_matrix A, int m, int n, a = S[i-1][j]; b = S[i][j]; - sigma = (a * b < 0) ? -1: 1; - a = abs_hwi (a); - b = abs_hwi (b); - factor = sigma * (a / b); + sigma = ((a < 0) ^ (b < 0)) ? -1: 1; + unsigned HOST_WIDE_INT abs_a = absu_hwi (a); + unsigned HOST_WIDE_INT abs_b = absu_hwi (b); + factor = sigma * (lambda_int)(abs_a / abs_b); lambda_matrix_row_add (S, n, i, i-1, -factor); std::swap (S[i], S[i-1]); @@ -4309,7 +4309,7 @@ analyze_subscript_affine_affine (tree chrec_a, tree *last_conflicts) { unsigned nb_vars_a, nb_vars_b, dim; - HOST_WIDE_INT gamma, gcd_alpha_beta; + lambda_int gamma, gcd_alpha_beta; lambda_matrix A, U, S; struct obstack scratch_obstack; -- 2.30.2