http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45884
Summary: Incorrect removal of check for "less than zero" after
adding value to (signed) long
Product: gcc
Version: 4.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: anders_j...@yahoo.com
Created attachment 21959
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=21959
Source (test.c), Makefile, Binaries, test.i, gcc -dumpspecs etc. See README.txt
When compiled with -O2, the below (val < 0) check is, under some conditions
(see attachment), optimized away:
...
long val10, val;
char *s;
...
if((*s >= '0') && (*s <= '9')) {
val10 = val * 10; // Skip overflow check, not the issue we are showing
val = val10 + (*s - '0');
/****** OPTIMIZED AWAY IN CASE OF -O2 ******/
if(val < 0) {
/* Overflow */
return -1;
}
...
}
Build on ubuntu (2.6.32-25-generic)
gcc version 4.4.3-4ubuntu5
machine i486-linux-gnu
Attaching complete test case with:
Makefile
Source (test.c)
Binaries
Result from compiling with -save-temps (test.i)
System configuration, gcc -dumpspecs, etc.
