https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61225
--- Comment #16 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Still in discussions in two threads about Combine and Compare-elim.
[PATCH] Fix PR 61225
https://gcc.gnu.org/ml/gcc-patches/2014-12/msg00558.html
https://gcc.gnu.org/ml/gcc
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64015
--- Comment #7 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Sorry for blocking your benchmark tests. I had reverted the ccmp patch.
I will rework the patch based on Richard Henderson's comments:
https://gcc.gnu.org/ml/gcc-patches/2014
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64015
--- Comment #2 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
You force it to register? In fact, I tend to not force it to register in
gen_ccmp_next, since it will introduce more overhead for ccmp, which
performance maybe worse.
My patch
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64015
--- Comment #5 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
It seams you always win with ccmp. Please go ahead for your patch and make sure
the following case work.
int
test (unsigned short a, unsigned char b)
{
return a 0xfff2 b
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61225
--- Comment #15 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Thank you for the reminder. I will rework the patch.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63917
--- Comment #3 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Root cause: r217646 enhances ifcvt to handle cbranchcc4 instruction. But ifcvt
does not check whether an insn will clobber CC or not, when moving it before
the cbranchcc4
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63917
--- Comment #2 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Thanks for the report. I can reproduce the FAIL on IA32. Since the patch does
not impact on -O0, it seams some library functions are wrong. I will
investigate it.
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zhenqiang.chen at arm dot com
Created attachment 33887
-- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33887action=edit
test case
Root cause: the fold_stmt swaps the operands, which leads to register
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63743
--- Comment #2 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
(In reply to Jakub Jelinek from comment #1)
Were we swapping operands before? I mean, if you rewrite the testcase to
swap the * arguments in the source, did you get the same
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63743
--- Comment #4 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
(In reply to Jakub Jelinek from comment #3)
(In reply to Zhenqiang Chen from comment #2)
(In reply to Jakub Jelinek from comment #1)
Were we swapping operands before? I
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61578
--- Comment #11 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Added updated CSiBE benchmark for GCC 4.8, GCC 4.9 and trunk.
It's obvious that excluding ip gives shorted code.
Then there is something on trunk that makes some project
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63210
--- Comment #4 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
(In reply to Ramana Radhakrishnan from comment #3)
Fixed is it? And does it fail in GCC 4.9 ?
Fixed on trunk. Same fail in GCC 4.9.
It is a performance issue. Do you think
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302
--- Comment #19 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
(In reply to John David Anglin from comment #18)
Hi Zhenqiang,
Do you plan to submit patch to gcc-patches soon?
Yes. It is in internal review process. I hope to send out
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302
--- Comment #14 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Created attachment 33608
-- https://gcc.gnu.org/bugzilla/attachment.cgi?id=33608action=edit
patch
After investigation, I found I mis-use tree_log2.
Please try the attached
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302
--- Comment #10 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
(In reply to dave.anglin from comment #8)
On 28-Sep-14, at 10:34 AM, dave.anglin at bell dot net wrote:
This is what I see on the trunk, but 4.9 is wrong. Possibly
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302
--- Comment #13 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
For 4.9, some function optimizes the code as:
Optimizing range tests x_2 -[-2147483648, -2147483648] and -[0, 0]
into (x_2 2147483647) != 0
For trunk
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63302
--- Comment #6 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
I double checked the function optimize_range_tests_diff. Overall, I think it
does the right thing. X86 and ARM work correctly. The ldil.c.169t.optimized is
bb 2:
x_2
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63210
--- Comment #1 from Zhenqiang Chen zhenqiang.chen at arm dot com ---
Here is a workaround patch to show the point.
diff --git a/gcc/ira-color.c b/gcc/ira-color.c
index e2ea359..1573fb5 100644
--- a/gcc/ira-color.c
+++ b/gcc/ira-color.c
: normal
Priority: P3
Component: rtl-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: zhenqiang.chen at arm dot com
Here is a case shown ira does not select the best register compared with gcc
4.8 for ARM Cortex-M0 with options:
-Os -mthumb -mcpu
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59535
Zhenqiang Chen zhenqiang.chen at arm dot com changed:
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