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ifcvt.c (noce_process_if_block): Fail if A or B modified between condition and jump.

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* ifcvt.c (noce_process_if_block): Fail if A or B modified
        between condition and jump.

From-SVN: r33689
This commit is contained in:
Richard Henderson 2000-05-04 16:22:26 -07:00
parent 00447f7d40
commit 0927ce96c9
1 changed files with 11 additions and 5 deletions
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16
gcc/ifcvt.c
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@ -1054,11 +1054,6 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb)
x = SET_DEST (set_a);
a = SET_SRC (set_a);
/* X may not be mentioned between cond_earliest and the jump. */
for (insn = jump; insn != if_info.cond_earliest; insn = PREV_INSN (insn))
if (INSN_P (insn) && reg_mentioned_p (x, insn))
return FALSE;
/* Look for the other potential set. Make sure we've got equivalent
destinations. */
/* ??? This is overconservative. Storing to two different mems is
@ -1088,6 +1083,17 @@ noce_process_if_block (test_bb, then_bb, else_bb, join_bb)
}
b = (set_b ? SET_SRC (set_b) : x);
/* X may not be mentioned in the range (cond_earliest, jump]. */
for (insn = jump; insn != if_info.cond_earliest; insn = PREV_INSN (insn))
if (INSN_P (insn) && reg_mentioned_p (x, insn))
return FALSE;
/* A and B may not be modified in the range [cond_earliest, jump). */
for (insn = if_info.cond_earliest; insn != jump; insn = NEXT_INSN (insn))
if (INSN_P (insn)
&& (modified_in_p (a, insn) || modified_in_p (b, insn)))
return FALSE;
/* Only operate on register destinations, and even then avoid extending
the lifetime of hard registers on small register class machines. */
orig_x = x;