From 4f34a9e8d5ffcef99a212180d58718b00bdbb7d2 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. (cherry picked from commit edb9330c29fe8a0a0b76df6fafd6a223a4d0e41f) --- 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 9bd17bcca92c..c0405ab32db9 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