mirror/gcc
2
0
Fork 0
mirror of git://gcc.gnu.org/git/gcc.git synced 2025-02-15 05:09:53 +08:00
Code Issues Packages Projects Releases Wiki Activity

m32c.c (m32c_compare_redundant): Avoid removing compares that may be indirectly affected by previous instructions.

Browse Source 
* config/m32c/m32c.c (m32c_compare_redundant): Avoid removing
compares that may be indirectly affected by previous instructions.

From-SVN: r149719
This commit is contained in:
DJ Delorie 2009-07-16 16:07:46 -04:00 committed by DJ Delorie
parent a41d064d96
commit b3c5a40978
2 changed files with 40 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
gcc/ChangeLog
View File

@ -1,3 +1,8 @@
2009-07-16 DJ Delorie <dj@redhat.com>
* config/m32c/m32c.c (m32c_compare_redundant): Avoid removing
compares that may be indirectly affected by previous instructions.
2009-07-16 Kaveh R. Ghazi <ghazi@caip.rutgers.edu>
* builtins.c (do_mpc_arg2): New.

36
gcc/config/m32c/m32c.c
View File

@ -4167,6 +4167,40 @@ m32c_compare_redundant (rtx cmp, rtx *operands)
#endif
return false;
}
/* Check for comparisons against memory - between volatiles and
aliases, we just can't risk this one. */
if (GET_CODE (operands[0]) == MEM
|| GET_CODE (operands[0]) == MEM)
{
#if DEBUG_CMP
fprintf(stderr, "comparisons with memory:\n");
debug_rtx(prev);
#endif
return false;
}
/* Check for PREV changing a register that's used to compute a
value in CMP, even if it doesn't otherwise change flags. */
if (GET_CODE (operands[0]) == REG
&& rtx_referenced_p (SET_DEST (PATTERN (prev)), operands[0]))
{
#if DEBUG_CMP
fprintf(stderr, "sub-value affected, op0:\n");
debug_rtx(prev);
#endif
return false;
}
if (GET_CODE (operands[1]) == REG
&& rtx_referenced_p (SET_DEST (PATTERN (prev)), operands[1]))
{
#if DEBUG_CMP
fprintf(stderr, "sub-value affected, op1:\n");
debug_rtx(prev);
#endif
return false;
}
} while (pflags == FLAGS_N);
#if DEBUG_CMP
fprintf(stderr, "previous flag-setting insn:\n");
@ -4251,7 +4285,7 @@ m32c_output_compare (rtx insn, rtx *operands)
}
#if DEBUG_CMP
fprintf(stderr, "cbranch: cmp needed: `%s'\n", templ);
fprintf(stderr, "cbranch: cmp needed: `%s'\n", templ + 1);
#endif
return templ + 1;
}