https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128568
Bug ID: 128568
Summary: sh: wrong code for loop
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: kristerw at gcc dot gnu.org
Blocks: 118443
Target Milestone: ---
Target: sh-elf
The function foo below is expected to execute two iterations of the loop when
called as
foo(&buf[5], -5, -1);
The expected output is therefore "1 0 1". But compiling the code with
optimization causes the loop to execute fewer iterations:
* Compiling with
sh-elf-gcc -ml -m4-single -O1 bug.c
makes it print "1 0 0" instead.
* Compiling with
sh-elf-gcc -ml -m4-single -Os bug.c
makes it print "0 0 0".
#include <stdio.h>
__attribute__((noipa)) void
foo (char *p, unsigned int start, unsigned int n)
{
for (unsigned int i = start; i < n; i += 2)
{
char *q = p + (int)i;
*q = 1;
}
}
int main()
{
char buf[5] = {0, 0, 0, 0, 0};
foo(&buf[5], -5, -1);
printf("%d %d %d\n", buf[0], buf[1], buf[2]);
return 0;
}
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118443
[Bug 118443] [Meta bug] Bugs triggered by and blocking more smtgcc testing
