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flow.c (propagate_block): Move initialization of mem_set_list ...

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* flow.c (propagate_block): Move initialization of mem_set_list ...
        (init_propagate_block_info): ... here.  Also track blocks with
        no successors; don't scan insns if ! PROP_SCAN_DEAD_CODE.

From-SVN: r34310
This commit is contained in:
Richard Henderson 2000-05-31 15:29:38 -07:00 committed by Richard Henderson
parent 1febe16ba4
commit eb7e5da2fc
2 changed files with 33 additions and 21 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2000-05-31 Richard Henderson <rth@cygnus.com>
* flow.c (propagate_block): Move initialization of mem_set_list ...
(init_propagate_block_info): ... here. Also track blocks with
no successors; don't scan insns if ! PROP_SCAN_DEAD_CODE.
2000-05-31 Richard Henderson <rth@cygnus.com>
* jump.c (jump_optimize_1): Revert 05-18 change.

48
gcc/flow.c
View File

@ -3639,7 +3639,8 @@ init_propagate_block_info (bb, live, local_set, flags)
/* If this block ends in a conditional branch, for each register live
from one side of the branch and not the other, record the register
as conditionally dead. */
if (GET_CODE (bb->end) == JUMP_INSN
if ((flags & (PROP_DEATH_NOTES | PROP_SCAN_DEAD_CODE))
&& GET_CODE (bb->end) == JUMP_INSN
&& any_condjump_p (bb->end))
{
regset_head diff_head;
@ -3717,6 +3718,31 @@ init_propagate_block_info (bb, live, local_set, flags)
}
#endif
/* If this block has no successors, any stores to the frame that aren't
used later in the block are dead. So make a pass over the block
recording any such that are made and show them dead at the end. We do
a very conservative and simple job here. */
if ((flags & PROP_SCAN_DEAD_CODE)
&& (bb->succ == NULL
|| (bb->succ->succ_next == NULL
&& bb->succ->dest == EXIT_BLOCK_PTR)))
{
rtx insn;
for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
if (GET_CODE (insn) == INSN
&& GET_CODE (PATTERN (insn)) == SET
&& GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
{
rtx mem = SET_DEST (PATTERN (insn));
if (XEXP (mem, 0) == frame_pointer_rtx
|| (GET_CODE (XEXP (mem, 0)) == PLUS
&& XEXP (XEXP (mem, 0), 0) == frame_pointer_rtx
&& GET_CODE (XEXP (XEXP (mem, 0), 1)) == CONST_INT))
pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
}
}
return pbi;
}
@ -3772,26 +3798,6 @@ propagate_block (bb, live, local_set, flags)
{ REG_BASIC_BLOCK (i) = REG_BLOCK_GLOBAL; });
}
/* If this block has no successors, any stores to the frame that aren't
used later in the block are dead. So make a pass over the block
recording any such that are made and show them dead at the end. We do
a very conservative and simple job here. */
if (bb->succ != 0 && bb->succ->succ_next == 0
&& bb->succ->dest == EXIT_BLOCK_PTR)
for (insn = bb->end; insn != bb->head; insn = PREV_INSN (insn))
if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SET
&& GET_CODE (SET_DEST (PATTERN (insn))) == MEM)
{
rtx mem = SET_DEST (PATTERN (insn));
if ((GET_CODE (XEXP (mem, 0)) == REG
&& REGNO (XEXP (mem, 0)) == FRAME_POINTER_REGNUM)
|| (GET_CODE (XEXP (mem, 0)) == PLUS
&& GET_CODE (XEXP (XEXP (mem, 0), 0)) == REG
&& REGNO (XEXP (XEXP (mem, 0), 0)) == FRAME_POINTER_REGNUM))
pbi->mem_set_list = alloc_EXPR_LIST (0, mem, pbi->mem_set_list);
}
/* Scan the block an insn at a time from end to beginning. */
for (insn = bb->end; ; insn = prev)