| Message ID | 20111117110713.GZ14325@bubble.grove.modra.org |
|---|---|
| State | New |
| Headers | show |
On Thu, Nov 17, 2011 at 6:07 AM, Alan Modra <amodra@gmail.com> wrote: > Lacking this pattern means the builtin __sync_synchronize() on powerpc > is just an asm with a memory clobber (see builtins.c), which is hardly > a "full memory barrier" as extend.texi says it should be. This patch > fixes multiple libgomp testsuite failures. Bootstrapped and > regression tested powerpc-linux. OK for mainline? > > * config/rs6000/sync.md: Duplicate hwsync as memory_barrier. This is one solution. Alternatively,the expander for "hwsync" could be renamed "memory_barrier" and all uses of gen_hwsync() changed to gen_memory_barrier(). I don't mind either way, but I would like Richard' opinion. Consistently using memory_barrier might be clearer to other GCC developers who look at the rs6000 port. Thanks, David
On 11/17/2011 04:50 AM, David Edelsohn wrote: > On Thu, Nov 17, 2011 at 6:07 AM, Alan Modra <amodra@gmail.com> wrote: >> Lacking this pattern means the builtin __sync_synchronize() on powerpc >> is just an asm with a memory clobber (see builtins.c), which is hardly >> a "full memory barrier" as extend.texi says it should be. This patch >> fixes multiple libgomp testsuite failures. Bootstrapped and >> regression tested powerpc-linux. OK for mainline? >> >> * config/rs6000/sync.md: Duplicate hwsync as memory_barrier. > > This is one solution. Alternatively,the expander for "hwsync" could > be renamed "memory_barrier" and all uses of gen_hwsync() changed to > gen_memory_barrier(). > > I don't mind either way, but I would like Richard' opinion. > Consistently using memory_barrier might be clearer to other GCC > developers who look at the rs6000 port. We're supposed to be looking at the new atomics patterns first, when they are available. Apparently __sync_synchronize got missed. It should be looking at mem_thread_fence before looking for memory_barrier. Will fix. r~
Index: gcc/config/rs6000/sync.md =================================================================== --- gcc/config/rs6000/sync.md (revision 181425) +++ gcc/config/rs6000/sync.md (working copy) @@ -53,6 +53,15 @@ (define_expand "mem_thread_fence" DONE; }) +(define_expand "memory_barrier" + [(set (match_dup 0) + (unspec:BLK [(match_dup 0)] UNSPEC_SYNC))] + "" +{ + operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode)); + MEM_VOLATILE_P (operands[0]) = 1; +}) + (define_expand "hwsync" [(set (match_dup 0) (unspec:BLK [(match_dup 0)] UNSPEC_SYNC))]