Jakub Jelinek <ja...@redhat.com> writes:
> On Tue, Feb 09, 2021 at 03:09:43PM +0100, Jakub Jelinek via Gcc-patches wrote:
>> > "TARGET_32BIT && TARGET_HAVE_LOB"
>> > - "le\t%|lr, %l0")
>> > + "*
>> > + if (get_attr_length (insn) == 4)
>> > + return \"le\\t%|lr, %l0\";
>> > + else
>> > + return \"subs\\t%|lr, #1\;bne\\t%l0\";
>> > + "
>>
>> Why not
>> {
>> if (get_attr_length (insn) == 4)
>> return "le\t%|lr, %l0";
>> else
>> return "subs\t%|lr, #1;bne\t%l0";
>> }
>> instead? Seems the arm backend uses "*..." more than the more modern {},
>> but one needs to backslash prefix a lot which makes it less readable?
>
> Where "more modern" is introduced 19.5 years ago ;)
>
> Jakub
I guess we really like traditions :)
Attached second version addressing this.
Thanks
Andrea
>From 7434e9519929affe8bcb7f4df2a775612cba0b18 Mon Sep 17 00:00:00 2001
From: Andrea Corallo <andrea.cora...@arm.com>
Date: Wed, 3 Feb 2021 15:21:54 +0100
Subject: [PATCH] arm: Low overhead loop handle long range branches [PR98931]
gcc/ChangeLog
2021-02-05 Andrea Corallo <andrea.cora...@arm.com>
* config/arm/thumb2.md: Generate alternative sequence to
handle long range branches.
gcc/testsuite/Changelog
2021-02-08 Andrea Corallo <andrea.cora...@arm.com>
* gcc.target/arm/pr98931.c: New testcase.
---
gcc/config/arm/thumb2.md | 13 ++++++++++++-
gcc/testsuite/gcc.target/arm/pr98931.c | 17 +++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/arm/pr98931.c
diff --git a/gcc/config/arm/thumb2.md b/gcc/config/arm/thumb2.md
index bd53bf320de..a032448654a 100644
--- a/gcc/config/arm/thumb2.md
+++ b/gcc/config/arm/thumb2.md
@@ -1719,7 +1719,18 @@
(set (reg:SI LR_REGNUM)
(plus:SI (reg:SI LR_REGNUM) (const_int -1)))])]
"TARGET_32BIT && TARGET_HAVE_LOB"
- "le\t%|lr, %l0")
+ {
+ if (get_attr_length (insn) == 4)
+ return "le\t%|lr, %l0";
+ else
+ return "subs\t%|lr, #1;bne\t%l0";
+ }
+ [(set (attr "length")
+ (if_then_else
+ (lt (minus (pc) (match_dup 0)) (const_int 1024))
+ (const_int 4)
+ (const_int 6)))
+ (set_attr "type" "branch")])
(define_expand "doloop_begin"
[(match_operand 0 "" "")
diff --git a/gcc/testsuite/gcc.target/arm/pr98931.c
b/gcc/testsuite/gcc.target/arm/pr98931.c
new file mode 100644
index 00000000000..313876a3912
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr98931.c
@@ -0,0 +1,17 @@
+/* { dg-do assemble } */
+/* { dg-skip-if "avoid conflicting multilib options" { *-*-* } { "-marm"
"-mcpu=*" } } */
+/* { dg-options "-march=armv8.1-m.main -O3
--param=max-completely-peeled-insns=1300 --save-temps" } */
+
+extern long long a[][20][26][26][22];
+
+void
+foo ()
+{
+ for (short d = 0; d + 1; d++)
+ for (unsigned e = 0; e < 25; e += 4)
+ for (unsigned f = 0; f < 25; f += 4)
+ for (int g = 0; g < 21; g += 4)
+ a[4][d][e][f][g] = 0;
+}
+
+/* { dg-final { scan-assembler-not {le\slr,\s\S*} } } */
--
2.20.1
