Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-07 Thread H.J. Lu
On Fri, Mar 6, 2015 at 8:36 AM, Jiong Wang jiong.w...@arm.com wrote: Wilco Dijkstra writes: Jeff Law wrote: Can you move pr45685.c into gcc.target/i386? I know Richi said next stage1, but given this fixes a performance regression for ARM and it's reverting rather than adding new code, I

RE: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-06 Thread Wilco Dijkstra
Jeff Law wrote: Can you move pr45685.c into gcc.target/i386? I know Richi said next stage1, but given this fixes a performance regression for ARM and it's reverting rather than adding new code, I think this is OK for the trunk with the testcase moved. So, OK with the testcase moved into

Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-06 Thread Jiong Wang
Wilco Dijkstra writes: Jeff Law wrote: Can you move pr45685.c into gcc.target/i386? I know Richi said next stage1, but given this fixes a performance regression for ARM and it's reverting rather than adding new code, I think this is OK for the trunk with the testcase moved. So, OK with

Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-04 Thread H.J. Lu
On Wed, Mar 4, 2015 at 9:10 AM, Jeff Law l...@redhat.com wrote: On 03/04/15 09:18, Wilco Dijkstra wrote: Jeff Law wrote: On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless

RE: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-04 Thread Wilco Dijkstra
Jeff Law wrote: On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional negate is extremely inefficient on most targets (5 sequentially dependent

Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-03-04 Thread Jeff Law
On 03/04/15 09:18, Wilco Dijkstra wrote: Jeff Law wrote: On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional negate is extremely inefficient on most

RE: [PATCH] Remove inefficient branchless conditional negate optimization

2015-02-27 Thread Wilco Dijkstra
Richard Biener wrote: On Thu, Feb 26, 2015 at 11:20 PM, Jeff Law l...@redhat.com wrote: On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional

Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-02-27 Thread Richard Biener
On Thu, Feb 26, 2015 at 11:20 PM, Jeff Law l...@redhat.com wrote: On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional negate is extremely inefficient

[PATCH] Remove inefficient branchless conditional negate optimization

2015-02-26 Thread Wilco Dijkstra
Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional negate is extremely inefficient on most targets (5 sequentially dependent instructions rather than 2 on AArch64). Since the underlying issue

Re: [PATCH] Remove inefficient branchless conditional negate optimization

2015-02-26 Thread Jeff Law
On 02/26/15 10:30, Wilco Dijkstra wrote: Several GCC versions ago a conditional negate optimization was introduced as a workaround for PR45685. However the branchless expansion for conditional negate is extremely inefficient on most targets (5 sequentially dependent instructions rather than 2