On Fri, Oct 16, 2015 at 12:44:05PM +0300, ville.syrjala@xxxxxxxxxxxxxxx wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > gem_pwrite_snooped was broken when the #pragma GCC stuff was added in > b04691b tests/gem_pwrite_snooped: disable const cast warning > > Apparently gcc treats '#pragma GCC' as a C statement. With the current > code memchr_inv() pretty much disappears entirely because gcc thinks > there's an unconditional return in the loop body. Or at least that's my > assumption. Put braces around the if body to fix it. > > This is the original asm: > 00000000000002f0 <memchr_inv.isra.0>: > 2f0: 48 85 f6 test %rsi,%rsi > 2f3: b8 00 00 00 00 mov $0x0,%eax > 2f8: 48 0f 45 c7 cmovne %rdi,%rax > 2fc: c3 retq > > This is with the fix: > 00000000000002f0 <memchr_inv.constprop.1>: > 2f0: 48 85 f6 test %rsi,%rsi > 2f3: 74 25 je 31a <memchr_inv.constprop.1+0x2a> > 2f5: 48 01 fe add %rdi,%rsi > 2f8: 80 3f ff cmpb $0xff,(%rdi) > 2fb: 48 8d 57 01 lea 0x1(%rdi),%rdx > 2ff: 74 11 je 312 <memchr_inv.constprop.1+0x22> > 301: eb 1a jmp 31d <memchr_inv.constprop.1+0x2d> > 303: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) > 308: 48 83 c2 01 add $0x1,%rdx > 30c: 80 7a ff ff cmpb $0xff,-0x1(%rdx) > 310: 75 0b jne 31d <memchr_inv.constprop.1+0x2d> > 312: 48 39 f2 cmp %rsi,%rdx > 315: 48 89 d7 mov %rdx,%rdi > 318: 75 ee jne 308 <memchr_inv.constprop.1+0x18> > 31a: 31 c0 xor %eax,%eax > 31c: c3 retq > 31d: 48 89 f8 mov %rdi,%rax > 320: c3 retq > > Cc: Thomas Wood <thomas.wood@xxxxxxxxx> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92227 > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> Bah, hangs head in shame. You'll see why. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
