OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

*** empty log message *** 

From-SVN: r321
This commit is contained in:
Richard Stallman 1992-02-14 19:54:07 +00:00
parent f8e30d7f57
commit 2d20b9dffe
1 changed files with 22 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
gcc/jump.c
View File

@ -1199,6 +1199,17 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
is not defined and the condition is tested by a separate compare
insn. This is because the code below assumes that the result
of the compare dies in the following branch. */
/* ??? This has to be turned off. The problem is that the
unconditional jump might indirectly end up branching to the
label between TEMP1 and TEMP. We can't detect this, in general,
since it may become a jump to there after further optimizations.
If that jump is done, it will be deleted, so we will retry
this optimization in the next pass, thus an infinite loop.
The present code prevents this by putting the jump after the
label, but this is not logically correct. */
#if 0
else if (this_is_condjump
/* Safe to skip USE and CLOBBER insns here
since they will not be deleted. */
@ -1260,9 +1271,9 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
/* Get the label out of the LABEL_REF. */
ultimate = XEXP (ultimate, 0);
/* Insert the jump after any USE or CLOBBER
that follows TEMP1. */
last_insn = prev_real_insn (temp);
/* Insert the jump immediately before TEMP, specifically
after the label that is between TEMP1 and TEMP. */
last_insn = PREV_INSN (temp);
/* If we would be branching to the next insn, the jump
would immediately be deleted and the re-inserted in
@ -1288,6 +1299,7 @@ jump_optimize (f, cross_jump, noop_moves, after_regscan)
}
}
}
#endif
/* Detect a conditional jump going to the same place
as an immediately following unconditional jump. */
else if (this_is_condjump
@ -2513,6 +2525,8 @@ sets_cc0_p (x)
/* Follow any unconditional jump at LABEL;
return the ultimate label reached by any such chain of jumps.
If LABEL is not followed by a jump, return LABEL.
If the chain loops or we can't find end, return LABEL,
since that tells caller to avoid changing the insn.
If RELOAD_COMPLETED is 0, we do not chain across a NOTE_INSN_LOOP_BEG or
a USE or CLOBBER. */
@ -2548,9 +2562,11 @@ follow_jumps (label)
/* If we have found a cycle, make the insn jump to itself. */
if (JUMP_LABEL (insn) == label)
break;
return label;
value = JUMP_LABEL (insn);
}
if (depth == 10)
return label;
return value;
}
@ -3098,7 +3114,8 @@ redirect_jump (jump, nlabel)
int label_index = nlabel ? INSN_UID (nlabel) : 0;
delete_from_jump_chain (jump);
if (label_index < max_jump_chain)
if (label_index < max_jump_chain
&& INSN_UID (jump) < max_jump_chain)
{
jump_chain[INSN_UID (jump)] = jump_chain[label_index];
jump_chain[label_index] = jump;