From 835d50c66aa5bde2f354a6e63a2afa7d2f76a05a Mon Sep 17 00:00:00 2001
From: Richard Sandiford <richard.sandiford@arm.com>
Date: Thu, 26 Sep 2019 07:38:21 +0000
Subject: [PATCH] [AArch64] Fix cost of (plus ... (const_int -C))
The PLUS handling in aarch64_rtx_costs only checked for nonnegative
constants, meaning that simple immediate subtractions like:
(set (reg R1) (plus (reg R2) (const_int -8)))
had a cost of two instructions.
2019-09-26 Richard Sandiford <richard.sandiford@arm.com>
gcc/
* config/aarch64/aarch64.c (aarch64_rtx_costs): Use
aarch64_plus_immediate rather than aarch64_uimm12_shift
to test for valid PLUS immediates.
From-SVN: r276140
---
gcc/ChangeLog | 6 ++++++
gcc/config/aarch64/aarch64.c | 2 +-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 678652419c2a..838257145b3e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-09-26 Richard Sandiford <richard.sandiford@arm.com>
+
+ * config/aarch64/aarch64.c (aarch64_rtx_costs): Use
+ aarch64_plus_immediate rather than aarch64_uimm12_shift
+ to test for valid PLUS immediates.
+
2019-09-25 Martin Jambor <mjambor@suse.cz>
* tree-sra.c (no_accesses_p): Remove.
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 56a4a47db73e..71d44de1d0a9 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -10753,7 +10753,7 @@ cost_plus:
}
if (GET_MODE_CLASS (mode) == MODE_INT
- && ((CONST_INT_P (op1) && aarch64_uimm12_shift (INTVAL (op1)))
+ && (aarch64_plus_immediate (op1, mode)
|| aarch64_sve_addvl_addpl_immediate (op1, mode)))
{
*cost += rtx_cost (op0, mode, PLUS, 0, speed);
--
GitLab