From: aoliva Date: Thu, 6 Dec 2018 23:18:19 +0000 (+0000) Subject: avoid null ptr deref in cselib_record_sets X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1212d8d1ae719996123b2ea2aca2cd3ffc8a492;p=thirdparty%2Fgcc.git avoid null ptr deref in cselib_record_sets Jeff Law tells me h8300-elf fails gcc.c-torture/compile/pr49029.c with -O2 -g -mint32 -mh. This patch fixes it. The problem is that strict low part handling in cselib_record_sets assumes src_elt is not NULL. That src_elt is taken from a strict low part set, but it won't always have a src_elt to begin with. In this case, it's because src is a volatile MEM; we don't record values for those. Although we could fix the problem by testing for a NULL src_elt before creating the zero extends corresponding to strict low part sets of formerly const0_rtx REGs, there's no point in recording the additional set that we won't be able to use anyway. We could still record that the whole register has a zero-extend of the value stored in the narrower-mode strict low part of the register, but is that of any use? I guess not, but if we find otherwise, we can change that later. for gcc/ChangeLog * cselib.c (cselib_record_sets): Skip strict low part sets with NULL src_elt. git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266873 138bc75d-0d04-0410-961f-82ee72b054a4 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index dc596889e34d..2dc7f43f8d35 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2018-12-06 Alexandre Oliva + + * cselib.c (cselib_record_sets): Skip strict low part sets + with NULL src_elt. + 2018-12-06 Paul A. Clarke PR target/88316 diff --git a/gcc/cselib.c b/gcc/cselib.c index 6d3a4078c689..4a68439455fd 100644 --- a/gcc/cselib.c +++ b/gcc/cselib.c @@ -2616,6 +2616,7 @@ cselib_record_sets (rtx_insn *insn) preserves the upper bits that di:SI=zero_extend(flags:CCNO<=0). */ scalar_int_mode mode; if (dest != orig + && sets[i].src_elt && cselib_record_sets_hook && REG_P (dest) && HARD_REGISTER_P (dest)