Update comment.

Stare at sanity checks but still fail to figure out how to make them
cheaper.  The register allocator's sanity checks consume 15%-20% of
the total running time of Vex.

git-svn-id: svn://svn.valgrind.org/vex/trunk@1093

diff --git a/VEX/priv/host-generic/reg_alloc2.c b/VEX/priv/host-generic/reg_alloc2.c
index ecc82551fed5942a9af4a923a5602e1e138182c1..fbbde4ec1a61decddf3732c181a51d8a008ac30d 100644 (file)
--- a/VEX/priv/host-generic/reg_alloc2.c
+++ b/VEX/priv/host-generic/reg_alloc2.c
@@ -618,8 +618,7 @@ HInstrArray* doRegisterAllocation (
    /* --------- Stage 3: allocate spill slots. --------- */
 
    /* Each spill slot is 8 bytes long.  For 128-bit vregs
-      we'll have to allocate two spill slots.  For now, tho,
-      ignore the 128-bit problem.
+      we have to allocate two spill slots.
 
       Do a rank-based allocation of vregs to spill slot numbers.  We
       put as few values as possible in spill slows, but nevertheless
@@ -641,7 +640,9 @@ HInstrArray* doRegisterAllocation (
 
       /* The spill slots are 64 bits in size.  That means, to spill a
          Vec128-class vreg, we'll need to find two adjacent spill
-         slots to use.  */
+         slots to use.  Note, this special-casing needs to happen for
+         all 128-bit sized register classes.  Currently though
+         HRcVector is the only such class. */
 
       if (vreg_lrs[j].reg_class != HRcVec128) {