http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54418
--- Comment #2 from Oleg Endo <olegendo at gcc dot gnu.org> 2012-08-30 22:18:34
UTC ---
Unfortunately I was not able to reproduce this case without the -fopenmp
option, and that option requires threads, which are not available on the sh-sim
config I've got here for testing. Kaz, could you please try out the following?
Index: gcc/config/sh/sh.md
===================================================================
--- gcc/config/sh/sh.md (revision 190781)
+++ gcc/config/sh/sh.md (working copy)
@@ -1043,13 +1043,19 @@
;; SImode unsigned integer comparisons
;; -------------------------------------------------------------------------
+;; Usually comparisons of 'unsigned int >= 0' are optimized away completely.
+;; However, especially when optimizations are off (e.g. -O0) such comparisons
+;; might remain and we have to handle them. If the '>= 0' case wasn't
+;; handled here, something else would just load a '0' into the second operand
+;; and do the comparison. We can do slightly better by just setting the
+;; T bit to '1'.
(define_insn_and_split "cmpgeusi_t"
[(set (reg:SI T_REG)
(geu:SI (match_operand:SI 0 "arith_reg_operand" "r")
- (match_operand:SI 1 "arith_reg_or_0_operand" "rN")))]
+ (match_operand:SI 1 "arith_reg_or_0_operand" "r")))]
"TARGET_SH1"
"cmp/hs %1,%0"
- "&& satisfies_constraint_Z (operands[0])"
+ "&& satisfies_constraint_Z (operands[1])"
[(set (reg:SI T_REG) (const_int 1))]
""
[(set_attr "type" "mt_group")])
Just in case, I'll also test this as usually on sh-sim.
