From edb9330c29fe8a0a0b76df6fafd6a223a4d0e41f Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 15 Jun 2022 10:54:48 +0200 Subject: [PATCH] tree-optimization/105969 - FPE with array diagnostics For a [0][0] array we have to be careful when dividing by the element size which is zero for the outermost dimension. Luckily the division is only for an overflow check which is pointless for array size zero. 2022-06-15 Richard Biener PR tree-optimization/105969 * gimple-ssa-sprintf.cc (get_origin_and_offset_r): Avoid division by zero in overflow check. * gcc.dg/pr105969.c: New testcase. --- gcc/gimple-ssa-sprintf.cc | 2 +- gcc/testsuite/gcc.dg/pr105969.c | 13 +++++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/pr105969.c diff --git a/gcc/gimple-ssa-sprintf.cc b/gcc/gimple-ssa-sprintf.cc index 6bd27302213b..a888b5ac7d51 100644 --- a/gcc/gimple-ssa-sprintf.cc +++ b/gcc/gimple-ssa-sprintf.cc @@ -2319,7 +2319,7 @@ get_origin_and_offset_r (tree x, HOST_WIDE_INT *fldoff, HOST_WIDE_INT *fldsize, if (byteoff < HOST_WIDE_INT_MAX && elbytes < HOST_WIDE_INT_MAX - && byteoff / elbytes == idx) + && (elbytes == 0 || byteoff / elbytes == idx)) { /* For in-bounds constant offsets into constant-sized arrays bump up *OFF, and for what's likely arrays or structs of diff --git a/gcc/testsuite/gcc.dg/pr105969.c b/gcc/testsuite/gcc.dg/pr105969.c new file mode 100644 index 000000000000..52c63fc2efe6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr105969.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-options "-Wall" } */ + +struct A +{ + char a[0][0][0]; +}; +extern struct A b[][2]; +void f (void) +{ + __builtin_sprintf (b[0][0].a[1][0], "%s", b[0][0].a[1][0]); /* { dg-warning "past the end" } */ + /* { dg-warning "overlaps destination" "" { target *-*-* } .-1 } */ +} -- 2.47.2