From: "Andre Vieira (lists)" <andre.simoesdiasvieira@arm.com>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: [PATCH][GCC][Arm]: MVE Don't use lsll for 32-bit shifts scalar
Date: Tue, 7 Apr 2020 11:42:47 +0100 [thread overview]
Message-ID: <bb65410a-0b4d-d7d8-f909-97c87c8de4f5@arm.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 591 bytes --]
Hi,
After fixing the v[id]wdups using the "moving the wrap parameter" into
the top-end of a DImode operand using a shift, I noticed we were using
lsll for 32-bit shifts in scalars, where we don't need to, as we can
simply do a move, which is much better if we don't need to use the
bottom part.
We can solve this in a better way, but for now this will do.
Regression tested on arm-none-eabi.
Is this OK for trunk?
2020-04-07 Andre Vieira <andre.simoesdiasvieira@arm.com>
* config/arm/arm.d (ashldi3): Don't use lsll for constant 32-bit
shifts.
[-- Attachment #2: mve_fix_lsll.patch --]
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diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 1a7ea0d701e5677965574d877d0fe4b2f5bc149f..6d5560398dae3d0ace0342b4907542d2a6865f70 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -4422,7 +4422,8 @@ (define_expand "ashldi3"
operands[2] = force_reg (SImode, operands[2]);
/* Armv8.1-M Mainline double shifts are not expanded. */
- if (arm_reg_or_long_shift_imm (operands[2], GET_MODE (operands[2])))
+ if (arm_reg_or_long_shift_imm (operands[2], GET_MODE (operands[2]))
+ && (REG_P (operands[2]) || INTVAL(operands[2]) != 32))
{
if (!reg_overlap_mentioned_p(operands[0], operands[1]))
emit_insn (gen_movdi (operands[0], operands[1]));
next reply other threads:[~2020-04-07 10:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-07 10:42 Andre Vieira (lists) [this message]
2020-04-07 14:06 ` Kyrylo Tkachov
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