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riscv-gcc-1
Commit 5621d717 by Jeff Law
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pa.c (remove_useless_addtr_insns): New function. 

        * pa/pa.c (remove_useless_addtr_insns): New function.
        (pa_reorg): Delete code to remove useless add,tr insns.
        Instead call remove_useless_addtr_insns.
        (output_function_prologue): Call remove_useless_addtr_insns
        to catch any add,tr insns created by reorg.

From-SVN: r12889
parent a998424b
Showing with 154 additions and 81 deletions
gcc/config/pa/pa.c
......@@ -1966,6 +1966,157 @@ output_ascii (file, p, size)
}
fputs ("\"\n", file);
}
/* Try to rewrite floating point comparisons & branches to avoid
useless add,tr insns.
CHECK_NOTES is nonzero if we should examine REG_DEAD notes
to see if FPCC is dead. CHECK_NOTES is nonzero for the
first attempt to remove useless add,tr insns. It is zero
for the second pass as reorg sometimes leaves bogus REG_DEAD
notes lying around.
When CHECK_NOTES is zero we can only eliminate add,tr insns
when there's a 1:1 correspondence between fcmp and ftest/fbranch
instructions. */
void
remove_useless_addtr_insns (insns, check_notes)
rtx insns;
int check_notes;
{
rtx insn;
int all;
static int pass = 0;
/* This is fairly cheap, so always run it when optimizing. */
if (optimize > 0)
{
int fcmp_count = 0;
int fbranch_count = 0;
/* Walk all the insns in this function looking for fcmp & fbranch
instructions. Keep track of how many of each we find. */
insns = get_insns ();
for (insn = insns; insn; insn = next_insn (insn))
{
rtx tmp;
/* Ignore anything that isn't an INSN or a JUMP_INSN. */
if (GET_CODE (insn) != INSN && GET_CODE (insn) != JUMP_INSN)
continue;
tmp = PATTERN (insn);
/* It must be a set. */
if (GET_CODE (tmp) != SET)
continue;
/* If the destination is CCFP, then we've found an fcmp insn. */
tmp = SET_DEST (tmp);
if (GET_CODE (tmp) == REG && REGNO (tmp) == 0)
{
fcmp_count++;
continue;
}
tmp = PATTERN (insn);
/* If this is an fbranch instruction, bump the fbranch counter. */
if (GET_CODE (tmp) == SET
&& SET_DEST (tmp) == pc_rtx
&& GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
&& GET_CODE (XEXP (SET_SRC (tmp), 0)) == NE
&& GET_CODE (XEXP (XEXP (SET_SRC (tmp), 0), 0)) == REG
&& REGNO (XEXP (XEXP (SET_SRC (tmp), 0), 0)) == 0)
{
fbranch_count++;
continue;
}
}
/* Find all floating point compare + branch insns. If possible,
reverse the comparison & the branch to avoid add,tr insns. */
for (insn = insns; insn; insn = next_insn (insn))
{
rtx tmp, next;
/* Ignore anything that isn't an INSN. */
if (GET_CODE (insn) != INSN)
continue;
tmp = PATTERN (insn);
/* It must be a set. */
if (GET_CODE (tmp) != SET)
continue;
/* The destination must be CCFP, which is register zero. */
tmp = SET_DEST (tmp);
if (GET_CODE (tmp) != REG || REGNO (tmp) != 0)
continue;
/* INSN should be a set of CCFP.
See if the result of this insn is used in a reversed FP
conditional branch. If so, reverse our condition and
the branch. Doing so avoids useless add,tr insns. */
next = next_insn (insn);
while (next)
{
/* Jumps, calls and labels stop our search. */
if (GET_CODE (next) == JUMP_INSN
|| GET_CODE (next) == CALL_INSN
|| GET_CODE (next) == CODE_LABEL)
break;
/* As does another fcmp insn. */
if (GET_CODE (next) == INSN
&& GET_CODE (PATTERN (next)) == SET
&& GET_CODE (SET_DEST (PATTERN (next))) == REG
&& REGNO (SET_DEST (PATTERN (next))) == 0)
break;
next = next_insn (next);
}
/* Is NEXT_INSN a branch? */
if (next
&& GET_CODE (next) == JUMP_INSN)
{
rtx pattern = PATTERN (next);
/* If it a reversed fp conditional branch (eg uses add,tr)
and CCFP dies, then reverse our conditional and the branch
to avoid the add,tr. */
if (GET_CODE (pattern) == SET
&& SET_DEST (pattern) == pc_rtx
&& GET_CODE (SET_SRC (pattern)) == IF_THEN_ELSE
&& GET_CODE (XEXP (SET_SRC (pattern), 0)) == NE
&& GET_CODE (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == REG
&& REGNO (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == 0
&& GET_CODE (XEXP (SET_SRC (pattern), 1)) == PC
&& (fcmp_count == fbranch_count
|| (check_notes
&& find_regno_note (next, REG_DEAD, 0))))
{
/* Reverse the branch. */
tmp = XEXP (SET_SRC (pattern), 1);
XEXP (SET_SRC (pattern), 1) = XEXP (SET_SRC (pattern), 2);
XEXP (SET_SRC (pattern), 2) = tmp;
INSN_CODE (next) = -1;
/* Reverse our condition. */
tmp = PATTERN (insn);
PUT_CODE (XEXP (tmp, 1),
reverse_condition (GET_CODE (XEXP (tmp, 1))));
}
}
}
}
pass = !pass;
}
/* You may have trouble believing this, but this is the HP-PA stack
layout. Wow.
......@@ -2233,6 +2384,8 @@ output_function_prologue (file, size)
}
else
total_code_bytes = -1;
remove_useless_addtr_insns (get_insns (), 0);
}
void
......@@ -5494,87 +5647,7 @@ pa_reorg (insns)
{
rtx insn;
/* This is fairly cheap, so always run it if optimizing. */
if (optimize > 0)
{
/* Find all floating point compare + branch insns. If possible,
reverse the comparison & the branch to avoid add,tr insns. */
insns = get_insns ();
for (insn = insns; insn; insn = NEXT_INSN (insn))
{
rtx tmp, next_insn;
/* Ignore anything that isn't an INSN. */
if (GET_CODE (insn) != INSN)
continue;
tmp = PATTERN (insn);
/* It must be a set. */
if (GET_CODE (tmp) != SET)
continue;
/* The destination must be CCFP, which is register zero. */
tmp = SET_DEST (tmp);
if (GET_CODE (tmp) != REG || REGNO (tmp) != 0)
continue;
/* INSN should be a set of CCFP.
See if the result of this insn is used in a reversed FP
conditional branch. If so, reverse our condition and
the branch. Doing so avoids useless add,tr insns. */
next_insn = NEXT_INSN (insn);
while (next_insn)
{
/* Jumps, calls and labels stop our search. */
if (GET_CODE (next_insn) == JUMP_INSN
|| GET_CODE (next_insn) == CALL_INSN
|| GET_CODE (next_insn) == CODE_LABEL)
break;
/* As does another fcmp insn. */
if (GET_CODE (next_insn) == INSN
&& GET_CODE (PATTERN (next_insn)) == SET
&& GET_CODE (SET_DEST (PATTERN (next_insn))) == REG
&& REGNO (SET_DEST (PATTERN (next_insn))) == 0)
break;
next_insn = NEXT_INSN (next_insn);
}
/* Is NEXT_INSN a branch? */
if (next_insn
&& GET_CODE (next_insn) == JUMP_INSN)
{
rtx pattern = PATTERN (next_insn);
/* If it a reversed fp conditional branch (eg uses add,tr)
and CCFP dies, then reverse our conditional and the branch
to avoid the add,tr. */
if (GET_CODE (pattern) == SET
&& SET_DEST (pattern) == pc_rtx
&& GET_CODE (SET_SRC (pattern)) == IF_THEN_ELSE
&& GET_CODE (XEXP (SET_SRC (pattern), 0)) == NE
&& GET_CODE (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == REG
&& REGNO (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == 0
&& GET_CODE (XEXP (SET_SRC (pattern), 1)) == PC
&& find_regno_note (next_insn, REG_DEAD, 0))
{
/* Reverse the branch. */
tmp = XEXP (SET_SRC (pattern), 1);
XEXP (SET_SRC (pattern), 1) = XEXP (SET_SRC (pattern), 2);
XEXP (SET_SRC (pattern), 2) = tmp;
INSN_CODE (next_insn) = -1;
/* Reverse our condition. */
tmp = PATTERN (insn);
PUT_CODE (XEXP (tmp, 1),
reverse_condition (GET_CODE (XEXP (tmp, 1))));
}
}
}
}
remove_useless_addtr_insns (insns, 1);
/* This is fairly cheap, so always run it if optimizing. */
if (optimize > 0)
......
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