re PR target/46915 (Wrong code is generated for conditional branch followed by zero length asm)
PR target/46915 * config/pa/pa.c (branch_to_delay_slot_p): Use next_active_insn instead of next_real_insn. Search forward checking for both ASM_INPUT and ASM_OPERANDS asms until exit condition is found. (branch_needs_nop_p): Likewise. (use_skip_p): New function. (output_cbranch): Use use_skip_p. (output_bb, output_bvb): Likewise. From-SVN: r168026
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John David Anglin
John David Anglin
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c50ebc7332
commit
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2 changed files with 84 additions and 33 deletions
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@ -1,3 +1,14 @@
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2010-12-18 John David Anglin <dave.anglin@nrc-cnrc.gc.ca>
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PR target/46915
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* config/pa/pa.c (branch_to_delay_slot_p): Use next_active_insn instead
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of next_real_insn. Search forward checking for both ASM_INPUT and
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ASM_OPERANDS asms until exit condition is found.
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(branch_needs_nop_p): Likewise.
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(use_skip_p): New function.
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(output_cbranch): Use use_skip_p.
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(output_bb, output_bvb): Likewise.
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2010-12-18 Kai Tietz <kai.tietz@onevision.com>
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PR target/36834
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@ -6188,35 +6188,92 @@ pa_scalar_mode_supported_p (enum machine_mode mode)
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}
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/* Return TRUE if INSN, a jump insn, has an unfilled delay slot and
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it branches to the next real instruction. Otherwise, return FALSE. */
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it branches into the delay slot. Otherwise, return FALSE. */
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static bool
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branch_to_delay_slot_p (rtx insn)
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{
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rtx jump_insn;
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if (dbr_sequence_length ())
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return FALSE;
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return next_real_insn (JUMP_LABEL (insn)) == next_real_insn (insn);
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jump_insn = next_active_insn (JUMP_LABEL (insn));
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while (insn)
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{
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insn = next_active_insn (insn);
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if (jump_insn == insn)
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return TRUE;
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/* We can't rely on the length of asms. So, we return FALSE when
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the branch is followed by an asm. */
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if (!insn
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|| GET_CODE (PATTERN (insn)) == ASM_INPUT
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|| extract_asm_operands (PATTERN (insn)) != NULL_RTX
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|| get_attr_length (insn) > 0)
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break;
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}
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return FALSE;
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}
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/* Return TRUE if INSN, a jump insn, needs a nop in its delay slot.
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/* Return TRUE if INSN, a forward jump insn, needs a nop in its delay slot.
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This occurs when INSN has an unfilled delay slot and is followed
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by an ASM_INPUT. Disaster can occur if the ASM_INPUT is empty and
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the jump branches into the delay slot. So, we add a nop in the delay
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slot just to be safe. This messes up our instruction count, but we
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don't know how big the ASM_INPUT insn is anyway. */
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by an asm. Disaster can occur if the asm is empty and the jump
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branches into the delay slot. So, we add a nop in the delay slot
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when this occurs. */
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static bool
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branch_needs_nop_p (rtx insn)
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{
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rtx next_insn;
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rtx jump_insn;
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if (dbr_sequence_length ())
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return FALSE;
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next_insn = next_real_insn (insn);
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return GET_CODE (PATTERN (next_insn)) == ASM_INPUT;
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jump_insn = next_active_insn (JUMP_LABEL (insn));
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while (insn)
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{
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insn = next_active_insn (insn);
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if (!insn || jump_insn == insn)
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return TRUE;
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if (!(GET_CODE (PATTERN (insn)) == ASM_INPUT
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|| extract_asm_operands (PATTERN (insn)) != NULL_RTX)
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&& get_attr_length (insn) > 0)
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break;
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}
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return FALSE;
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}
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/* Return TRUE if INSN, a forward jump insn, can use nullification
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to skip the following instruction. This avoids an extra cycle due
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to a mis-predicted branch when we fall through. */
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static bool
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use_skip_p (rtx insn)
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{
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rtx jump_insn = next_active_insn (JUMP_LABEL (insn));
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while (insn)
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{
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insn = next_active_insn (insn);
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/* We can't rely on the length of asms, so we can't skip asms. */
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if (!insn
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|| GET_CODE (PATTERN (insn)) == ASM_INPUT
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|| extract_asm_operands (PATTERN (insn)) != NULL_RTX)
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break;
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if (get_attr_length (insn) == 4
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&& jump_insn == next_active_insn (insn))
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return TRUE;
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if (get_attr_length (insn) > 0)
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break;
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}
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return FALSE;
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}
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/* This routine handles all the normal conditional branch sequences we
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@ -6230,7 +6287,7 @@ const char *
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output_cbranch (rtx *operands, int negated, rtx insn)
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{
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static char buf[100];
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int useskip = 0;
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bool useskip;
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int nullify = INSN_ANNULLED_BRANCH_P (insn);
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int length = get_attr_length (insn);
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int xdelay;
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@ -6268,12 +6325,7 @@ output_cbranch (rtx *operands, int negated, rtx insn)
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/* A forward branch over a single nullified insn can be done with a
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comclr instruction. This avoids a single cycle penalty due to
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mis-predicted branch if we fall through (branch not taken). */
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if (length == 4
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&& next_real_insn (insn) != 0
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&& get_attr_length (next_real_insn (insn)) == 4
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&& JUMP_LABEL (insn) == next_nonnote_insn (next_real_insn (insn))
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&& nullify)
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useskip = 1;
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useskip = (length == 4 && nullify) ? use_skip_p (insn) : FALSE;
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switch (length)
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{
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@ -6561,7 +6613,7 @@ const char *
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output_bb (rtx *operands ATTRIBUTE_UNUSED, int negated, rtx insn, int which)
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{
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static char buf[100];
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int useskip = 0;
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bool useskip;
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int nullify = INSN_ANNULLED_BRANCH_P (insn);
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int length = get_attr_length (insn);
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int xdelay;
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@ -6587,13 +6639,7 @@ output_bb (rtx *operands ATTRIBUTE_UNUSED, int negated, rtx insn, int which)
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/* A forward branch over a single nullified insn can be done with a
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extrs instruction. This avoids a single cycle penalty due to
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mis-predicted branch if we fall through (branch not taken). */
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if (length == 4
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&& next_real_insn (insn) != 0
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&& get_attr_length (next_real_insn (insn)) == 4
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&& JUMP_LABEL (insn) == next_nonnote_insn (next_real_insn (insn))
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&& nullify)
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useskip = 1;
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useskip = (length == 4 && nullify) ? use_skip_p (insn) : FALSE;
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switch (length)
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{
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@ -6752,7 +6798,7 @@ const char *
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output_bvb (rtx *operands ATTRIBUTE_UNUSED, int negated, rtx insn, int which)
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{
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static char buf[100];
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int useskip = 0;
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bool useskip;
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int nullify = INSN_ANNULLED_BRANCH_P (insn);
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int length = get_attr_length (insn);
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int xdelay;
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@ -6778,13 +6824,7 @@ output_bvb (rtx *operands ATTRIBUTE_UNUSED, int negated, rtx insn, int which)
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/* A forward branch over a single nullified insn can be done with a
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extrs instruction. This avoids a single cycle penalty due to
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mis-predicted branch if we fall through (branch not taken). */
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if (length == 4
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&& next_real_insn (insn) != 0
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&& get_attr_length (next_real_insn (insn)) == 4
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&& JUMP_LABEL (insn) == next_nonnote_insn (next_real_insn (insn))
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&& nullify)
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useskip = 1;
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useskip = (length == 4 && nullify) ? use_skip_p (insn) : FALSE;
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switch (length)
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{
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