Hi all,
This patch fixes the gcc.dg/ifcvt-2.c test for x86_64 where we were failing to
if-convert.
This was because in my patch at
https://gcc.gnu.org/viewcvs/gcc?view=revision&revision=228194
which tried to emit a SET to move the source of insn_a or insn_b (that came
from the test block)
into a temporary. A SET however, is not always enough. For example, on x86_64
in order for the
resulting insn to be recognised it frequently needs to be in PARALLEL with a
(clobber (reg:CC FLAGS_REG)).
This leads to the insn not being recognised.
So this patch removes that SET and instead generates a couple of temporary
pseudos that gets passed
on a bit later to the code that loads the operands into registers when they're
not general_operand.
This way we just modify the existing (recognisable) sets, allowing us to
if-convert the testcase.
Bootstrapped and tested on x86_64, arm, aarch64.
Ok for trunk?
Thanks,
Kyrill
2015-10-27 Kyrylo Tkachov <kyrylo.tkac...@arm.com>
PR rtl-optimization/67749
* ifcvt.c (noce_try_cmove_arith): Do not emit move in IF-ELSE
case before emitting the two blocks. Instead modify the register
in the corresponding final insn of the basic block.
commit d58740af39ceaf2d654cf3feff97b39fb6da3e82
Author: Kyrylo Tkachov <kyrylo.tkac...@arm.com>
Date: Tue Sep 29 13:44:21 2015 +0100
[RTL-ifcvt] PR rtl-optimization/67749
diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index 8846e69..7c6e7ca 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -2135,38 +2135,29 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
emit might clobber the register used by B or A, so move it to a pseudo
first. */
+ rtx tmp_a = NULL_RTX;
+ rtx tmp_b = NULL_RTX;
+
if (b_simple || !else_bb)
- {
- rtx tmp_b = gen_reg_rtx (x_mode);
- /* Perform the simplest kind of set. The register allocator
- should remove it if it's not actually needed. If this set is not
- a valid insn (can happen on the is_mem path) then end_ifcvt_sequence
- will cancel the whole sequence. Don't try any of the fallback paths
- from noce_emit_move_insn since we want this to be the simplest kind
- of move. */
- emit_insn (gen_rtx_SET (tmp_b, b));
- b = tmp_b;
- }
+ tmp_b = gen_reg_rtx (x_mode);
if (a_simple || !then_bb)
- {
- rtx tmp_a = gen_reg_rtx (x_mode);
- emit_insn (gen_rtx_SET (tmp_a, a));
- a = tmp_a;
- }
+ tmp_a = gen_reg_rtx (x_mode);
orig_a = a;
orig_b = b;
rtx emit_a = NULL_RTX;
rtx emit_b = NULL_RTX;
-
+ rtx_insn *tmp_insn = NULL;
+ bool modified_in_a = false;
+ bool modified_in_b = false;
/* If either operand is complex, load it into a register first.
The best way to do this is to copy the original insn. In this
way we preserve any clobbers etc that the insn may have had.
This is of course not possible in the IS_MEM case. */
- if (! general_operand (a, GET_MODE (a)))
+ if (! general_operand (a, GET_MODE (a)) || tmp_a)
{
if (is_mem)
@@ -2174,36 +2165,51 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
rtx reg = gen_reg_rtx (GET_MODE (a));
emit_a = gen_rtx_SET (reg, a);
}
- else if (! insn_a)
- goto end_seq_and_fail;
else
{
- a = gen_reg_rtx (GET_MODE (a));
- rtx_insn *copy_of_a = as_a <rtx_insn *> (copy_rtx (insn_a));
- rtx set = single_set (copy_of_a);
- SET_DEST (set) = a;
+ if (insn_a)
+ {
+ a = tmp_a ? tmp_a : gen_reg_rtx (GET_MODE (a));
+
+ rtx_insn *copy_of_a = as_a <rtx_insn *> (copy_rtx (insn_a));
+ rtx set = single_set (copy_of_a);
+ SET_DEST (set) = a;
- emit_a = PATTERN (copy_of_a);
+ emit_a = PATTERN (copy_of_a);
+ }
+ else
+ {
+ rtx tmp_reg = tmp_a ? tmp_a : gen_reg_rtx (GET_MODE (a));
+ emit_a = gen_rtx_SET (tmp_reg, a);
+ a = tmp_reg;
+ }
}
}
- if (! general_operand (b, GET_MODE (b)))
+ if (! general_operand (b, GET_MODE (b)) || tmp_b)
{
if (is_mem)
{
rtx reg = gen_reg_rtx (GET_MODE (b));
emit_b = gen_rtx_SET (reg, b);
}
- else if (! insn_b)
- goto end_seq_and_fail;
else
{
- b = gen_reg_rtx (GET_MODE (b));
- rtx_insn *copy_of_b = as_a <rtx_insn *> (copy_rtx (insn_b));
- rtx set = single_set (copy_of_b);
+ if (insn_b)
+ {
+ b = tmp_b ? tmp_b : gen_reg_rtx (GET_MODE (b));
+ rtx_insn *copy_of_b = as_a <rtx_insn *> (copy_rtx (insn_b));
+ rtx set = single_set (copy_of_b);
- SET_DEST (set) = b;
- emit_b = PATTERN (copy_of_b);
+ SET_DEST (set) = b;
+ emit_b = PATTERN (copy_of_b);
+ }
+ else
+ {
+ rtx tmp_reg = tmp_b ? tmp_b : gen_reg_rtx (GET_MODE (b));
+ emit_b = gen_rtx_SET (tmp_reg, b);
+ b = tmp_reg;
+ }
}
}
@@ -2211,16 +2217,35 @@ noce_try_cmove_arith (struct noce_if_info *if_info)
swap insn that sets up A with the one that sets up B. If even
that doesn't help, punt. */
- if (emit_a && modified_in_p (orig_b, emit_a))
- {
- if (modified_in_p (orig_a, emit_b))
- goto end_seq_and_fail;
+ modified_in_a = emit_a != NULL_RTX && modified_in_p (orig_b, emit_a);
+ if (tmp_b && then_bb)
+ {
+ FOR_BB_INSNS (then_bb, tmp_insn)
+ if (modified_in_p (orig_b, tmp_insn))
+ {
+ modified_in_a = true;
+ break;
+ }
- if (else_bb && !b_simple)
+ }
+ if (emit_a && modified_in_a)
+ {
+ modified_in_b = emit_b != NULL_RTX && modified_in_p (orig_a, emit_b);
+ if (tmp_b && else_bb)
{
- if (!noce_emit_bb (emit_b, else_bb, b_simple))
- goto end_seq_and_fail;
+ FOR_BB_INSNS (else_bb, tmp_insn)
+ if (modified_in_p (orig_a, tmp_insn))
+ {
+ modified_in_b = true;
+ break;
+ }
+
}
+ if (modified_in_b)
+ goto end_seq_and_fail;
+
+ if (!noce_emit_bb (emit_b, else_bb, b_simple))
+ goto end_seq_and_fail;
if (!noce_emit_bb (emit_a, then_bb, a_simple))
goto end_seq_and_fail;
