Re: [PATCH v3 2/7] ifcvt: Allow constants for noce_convert_multiple.

[Robin Dapp via Gcc-patches]

Posting the ChangeLog before pushing.

--

gcc/ChangeLog:

* ifcvt.c (noce_convert_multiple_sets): Allow constants.
(bb_ok_for_noce_convert_multiple_sets): Likewise.

Re: [PATCH v3 2/7] ifcvt: Allow constants for noce_convert_multiple.

[Jeff Law via Gcc-patches]

On 12/6/2021 11:43 AM, Robin Dapp via Gcc-patches wrote:

This lifts the restriction of not allowing constants for
noce_convert_multiple.  The code later checks if a valid sequence
is produced anyway.
---
  gcc/ifcvt.c | 13 -
  1 file changed, 8 insertions(+), 5 deletions(-)

Fine with a ChangeLog once the prereqs are approved.

jeff

[PATCH v3 2/7] ifcvt: Allow constants for noce_convert_multiple.

[Robin Dapp via Gcc-patches]

This lifts the restriction of not allowing constants for
noce_convert_multiple.  The code later checks if a valid sequence
is produced anyway.
---
 gcc/ifcvt.c | 13 -
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c
index c98668d5646..4642176957e 100644
--- a/gcc/ifcvt.c
+++ b/gcc/ifcvt.c
@@ -3282,7 +3282,9 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
 we'll end up trying to emit r4:HI = cond ? (r1:SI) : (r3:HI).
 Wrap the two cmove operands into subregs if appropriate to prevent
 that.  */
-  if (GET_MODE (new_val) != GET_MODE (temp))
+
+  if (!CONSTANT_P (new_val)
+ && GET_MODE (new_val) != GET_MODE (temp))
{
  machine_mode src_mode = GET_MODE (new_val);
  machine_mode dst_mode = GET_MODE (temp);
@@ -3293,7 +3295,8 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
}
  new_val = lowpart_subreg (dst_mode, new_val, src_mode);
}
-  if (GET_MODE (old_val) != GET_MODE (temp))
+  if (!CONSTANT_P (old_val)
+ && GET_MODE (old_val) != GET_MODE (temp))
{
  machine_mode src_mode = GET_MODE (old_val);
  machine_mode dst_mode = GET_MODE (temp);
@@ -3435,9 +3438,9 @@ bb_ok_for_noce_convert_multiple_sets (basic_block test_bb)
   if (!REG_P (dest))
return false;
 
-  if (!(REG_P (src)
-  || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
-  && subreg_lowpart_p (src
+  if (!((REG_P (src) || CONSTANT_P (src))
+   || (GET_CODE (src) == SUBREG && REG_P (SUBREG_REG (src))
+ && subreg_lowpart_p (src
return false;
 
   /* Destination must be appropriate for a conditional write.  */
-- 
2.31.1