Changes to make this usable for ARM/Thumb.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2662 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Fix incorrect comment.


git-svn-id: svn://svn.valgrind.org/vex/trunk@2663 8f6e269a-dfd6-0310-a8e1-e2731360e62c
Infrastructure cleanup: change type of the condition field of
IRExpr_Mux0X from Ity_I8 to Ity_I1.  This makes more sense, makes it
consistent with condition fields in IRStmt_Dirty and IRStmt_Exit, and
avoids some pointless 1Uto8 casting of the condition, in many cases.
Fixes for s390 are from Florian.

Also, make a small extension to ir_opt.c, that allows the constant
folder to look backwards through arbitrary expressions even in flat
IR.  This makes it possible to do arbitrary tree folding in ir_opt,
which is where it belongs.  Use this to implement the folding rule
CmpNE32(1Uto32(b), 0) ==> b.



git-svn-id: svn://svn.valgrind.org/vex/trunk@2664 8f6e269a-dfd6-0310-a8e1-e2731360e62c