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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
This commit is contained in:
Jeff Law
parent
a998424bec
commit
5621d7177e
@ -1966,6 +1966,157 @@ output_ascii (file, p, size)
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}
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fputs ("\"\n", file);
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}
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/* Try to rewrite floating point comparisons & branches to avoid
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useless add,tr insns.
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CHECK_NOTES is nonzero if we should examine REG_DEAD notes
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to see if FPCC is dead. CHECK_NOTES is nonzero for the
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first attempt to remove useless add,tr insns. It is zero
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for the second pass as reorg sometimes leaves bogus REG_DEAD
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notes lying around.
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When CHECK_NOTES is zero we can only eliminate add,tr insns
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when there's a 1:1 correspondence between fcmp and ftest/fbranch
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instructions. */
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void
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remove_useless_addtr_insns (insns, check_notes)
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rtx insns;
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int check_notes;
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{
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rtx insn;
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int all;
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static int pass = 0;
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/* This is fairly cheap, so always run it when optimizing. */
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if (optimize > 0)
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{
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int fcmp_count = 0;
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int fbranch_count = 0;
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/* Walk all the insns in this function looking for fcmp & fbranch
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instructions. Keep track of how many of each we find. */
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insns = get_insns ();
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for (insn = insns; insn; insn = next_insn (insn))
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{
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rtx tmp;
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/* Ignore anything that isn't an INSN or a JUMP_INSN. */
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if (GET_CODE (insn) != INSN && GET_CODE (insn) != JUMP_INSN)
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continue;
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tmp = PATTERN (insn);
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/* It must be a set. */
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if (GET_CODE (tmp) != SET)
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continue;
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/* If the destination is CCFP, then we've found an fcmp insn. */
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tmp = SET_DEST (tmp);
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if (GET_CODE (tmp) == REG && REGNO (tmp) == 0)
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{
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fcmp_count++;
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continue;
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}
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tmp = PATTERN (insn);
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/* If this is an fbranch instruction, bump the fbranch counter. */
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if (GET_CODE (tmp) == SET
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&& SET_DEST (tmp) == pc_rtx
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&& GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE
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&& GET_CODE (XEXP (SET_SRC (tmp), 0)) == NE
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&& GET_CODE (XEXP (XEXP (SET_SRC (tmp), 0), 0)) == REG
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&& REGNO (XEXP (XEXP (SET_SRC (tmp), 0), 0)) == 0)
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{
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fbranch_count++;
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continue;
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}
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}
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/* Find all floating point compare + branch insns. If possible,
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reverse the comparison & the branch to avoid add,tr insns. */
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for (insn = insns; insn; insn = next_insn (insn))
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{
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rtx tmp, next;
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/* Ignore anything that isn't an INSN. */
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if (GET_CODE (insn) != INSN)
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continue;
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tmp = PATTERN (insn);
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/* It must be a set. */
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if (GET_CODE (tmp) != SET)
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continue;
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/* The destination must be CCFP, which is register zero. */
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tmp = SET_DEST (tmp);
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if (GET_CODE (tmp) != REG || REGNO (tmp) != 0)
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continue;
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/* INSN should be a set of CCFP.
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See if the result of this insn is used in a reversed FP
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conditional branch. If so, reverse our condition and
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the branch. Doing so avoids useless add,tr insns. */
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next = next_insn (insn);
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while (next)
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{
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/* Jumps, calls and labels stop our search. */
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if (GET_CODE (next) == JUMP_INSN
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|| GET_CODE (next) == CALL_INSN
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|| GET_CODE (next) == CODE_LABEL)
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break;
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/* As does another fcmp insn. */
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if (GET_CODE (next) == INSN
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&& GET_CODE (PATTERN (next)) == SET
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&& GET_CODE (SET_DEST (PATTERN (next))) == REG
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&& REGNO (SET_DEST (PATTERN (next))) == 0)
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break;
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next = next_insn (next);
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}
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/* Is NEXT_INSN a branch? */
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if (next
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&& GET_CODE (next) == JUMP_INSN)
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{
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rtx pattern = PATTERN (next);
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/* If it a reversed fp conditional branch (eg uses add,tr)
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and CCFP dies, then reverse our conditional and the branch
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to avoid the add,tr. */
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if (GET_CODE (pattern) == SET
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&& SET_DEST (pattern) == pc_rtx
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&& GET_CODE (SET_SRC (pattern)) == IF_THEN_ELSE
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&& GET_CODE (XEXP (SET_SRC (pattern), 0)) == NE
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&& GET_CODE (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == REG
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&& REGNO (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == 0
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&& GET_CODE (XEXP (SET_SRC (pattern), 1)) == PC
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&& (fcmp_count == fbranch_count
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|| (check_notes
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&& find_regno_note (next, REG_DEAD, 0))))
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{
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/* Reverse the branch. */
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tmp = XEXP (SET_SRC (pattern), 1);
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XEXP (SET_SRC (pattern), 1) = XEXP (SET_SRC (pattern), 2);
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XEXP (SET_SRC (pattern), 2) = tmp;
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INSN_CODE (next) = -1;
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/* Reverse our condition. */
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tmp = PATTERN (insn);
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PUT_CODE (XEXP (tmp, 1),
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reverse_condition (GET_CODE (XEXP (tmp, 1))));
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}
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}
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}
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}
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pass = !pass;
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}
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/* You may have trouble believing this, but this is the HP-PA stack
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layout. Wow.
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@ -2233,6 +2384,8 @@ output_function_prologue (file, size)
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}
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else
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total_code_bytes = -1;
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remove_useless_addtr_insns (get_insns (), 0);
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}
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void
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@ -5494,87 +5647,7 @@ pa_reorg (insns)
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{
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rtx insn;
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/* This is fairly cheap, so always run it if optimizing. */
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if (optimize > 0)
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{
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/* Find all floating point compare + branch insns. If possible,
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reverse the comparison & the branch to avoid add,tr insns. */
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insns = get_insns ();
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for (insn = insns; insn; insn = NEXT_INSN (insn))
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{
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rtx tmp, next_insn;
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/* Ignore anything that isn't an INSN. */
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if (GET_CODE (insn) != INSN)
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continue;
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tmp = PATTERN (insn);
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/* It must be a set. */
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if (GET_CODE (tmp) != SET)
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continue;
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/* The destination must be CCFP, which is register zero. */
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tmp = SET_DEST (tmp);
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if (GET_CODE (tmp) != REG || REGNO (tmp) != 0)
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continue;
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/* INSN should be a set of CCFP.
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See if the result of this insn is used in a reversed FP
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conditional branch. If so, reverse our condition and
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the branch. Doing so avoids useless add,tr insns. */
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next_insn = NEXT_INSN (insn);
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while (next_insn)
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{
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/* Jumps, calls and labels stop our search. */
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if (GET_CODE (next_insn) == JUMP_INSN
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|| GET_CODE (next_insn) == CALL_INSN
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|| GET_CODE (next_insn) == CODE_LABEL)
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break;
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/* As does another fcmp insn. */
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if (GET_CODE (next_insn) == INSN
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&& GET_CODE (PATTERN (next_insn)) == SET
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&& GET_CODE (SET_DEST (PATTERN (next_insn))) == REG
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&& REGNO (SET_DEST (PATTERN (next_insn))) == 0)
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break;
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next_insn = NEXT_INSN (next_insn);
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}
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/* Is NEXT_INSN a branch? */
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if (next_insn
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&& GET_CODE (next_insn) == JUMP_INSN)
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{
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rtx pattern = PATTERN (next_insn);
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/* If it a reversed fp conditional branch (eg uses add,tr)
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and CCFP dies, then reverse our conditional and the branch
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to avoid the add,tr. */
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if (GET_CODE (pattern) == SET
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&& SET_DEST (pattern) == pc_rtx
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&& GET_CODE (SET_SRC (pattern)) == IF_THEN_ELSE
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&& GET_CODE (XEXP (SET_SRC (pattern), 0)) == NE
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&& GET_CODE (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == REG
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&& REGNO (XEXP (XEXP (SET_SRC (pattern), 0), 0)) == 0
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&& GET_CODE (XEXP (SET_SRC (pattern), 1)) == PC
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&& find_regno_note (next_insn, REG_DEAD, 0))
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{
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/* Reverse the branch. */
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tmp = XEXP (SET_SRC (pattern), 1);
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XEXP (SET_SRC (pattern), 1) = XEXP (SET_SRC (pattern), 2);
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XEXP (SET_SRC (pattern), 2) = tmp;
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INSN_CODE (next_insn) = -1;
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/* Reverse our condition. */
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tmp = PATTERN (insn);
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PUT_CODE (XEXP (tmp, 1),
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reverse_condition (GET_CODE (XEXP (tmp, 1))));
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}
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}
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}
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}
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remove_useless_addtr_insns (insns, 1);
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/* This is fairly cheap, so always run it if optimizing. */
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if (optimize > 0)
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