X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;ds=sidebyside;f=rts%2Fsm%2FGCThread.h;h=5646eddb510e168f6ea74a10a7ca209a456fd0d6;hb=f9d5c95fb4b4989ce4da8005793d3730452a33a9;hp=c563d95efdae2d5e7287489a87c9547b18e22eff;hpb=ed45b268cba82ed698853b4a1c3d35e904ec020d;p=ghc-hetmet.git

diff --git a/rts/sm/GCThread.h b/rts/sm/GCThread.h
index c563d95..5646edd 100644
--- a/rts/sm/GCThread.h
+++ b/rts/sm/GCThread.h
@@ -209,10 +209,15 @@ extern gc_thread **gc_threads;
 
 #define SET_GCT(to) gct = (to)
 
-#if defined(sparc_HOST_ARCH)
+#if defined(sparc_HOST_ARCH) || defined(i386_HOST_ARCH)
 // Don't use REG_base or R1 for gct on SPARC because they're getting clobbered 
 //	by something else. Not sure what yet. -- BL 2009/01/03
 
+// Using __thread is better than stealing a register on x86, because
+// we have too few registers available.  In my tests it was worth
+// about 5% in GC performance, but of course that might change as gcc
+// improves. -- SDM 2009/04/03
+
 extern __thread gc_thread* gct;
 #define DECLARE_GCT __thread gc_thread* gct;