Hi,
When a cbranch immediately follows an SH2A nott insn, the branch
condition can be inverted and the nott insn can be deleted. This is
what the attached patch makes the sh_treg_combine pass do.
Tested with
make -k check RUNTESTFLAGS="--target_board=sh-sim
\{-m2/-ml,-m2/-mb,-m2a/-mb,-m4/-ml,-m4/-mb,-m4a/-ml,-m4a/-mb}"
Committed as r218847.
Cheers,
Oleg
gcc/ChangeLog:
PR target/51244
* config/sh/sh_treg_combine.cc (sh_treg_combine::try_optimize_cbranch):
Combine ccreg inversion and cbranch into inverted cbranch.
Index: gcc/config/sh/sh_treg_combine.cc
===================================================================
--- gcc/config/sh/sh_treg_combine.cc (revision 218722)
+++ gcc/config/sh/sh_treg_combine.cc (working copy)
@@ -1339,9 +1339,17 @@
// for now we limit the search to the current basic block.
trace.setcc = find_set_of_reg_bb (m_ccreg, prev_nonnote_insn_bb (insn));
- if (!is_cmp_eq_zero (trace.setcc.set_src ()))
+ if (trace.setcc.set_src () == NULL_RTX)
log_return_void ("could not find set of ccreg in current BB\n");
+ if (!is_cmp_eq_zero (trace.setcc.set_src ())
+ && !is_inverted_ccreg (trace.setcc.set_src ()))
+ {
+ log_msg ("unsupported set of ccreg in current BB: ");
+ log_rtx (trace.setcc.set_src ());
+ log_return_void ("\n");
+ }
+
rtx trace_reg = XEXP (trace.setcc.set_src (), 0);
log_msg ("set of ccreg:\n");
@@ -1358,6 +1366,19 @@
log_return_void ("\nbecause it's volatile\n");
}
+ // If the ccreg is inverted before cbranch try inverting the branch
+ // condition.
+ if (is_inverted_ccreg (trace.setcc.set_src ()))
+ {
+ if (!trace.can_invert_condition ())
+ log_return_void ("branch condition can't be inverted - aborting\n");
+
+ if (try_invert_branch_condition (trace))
+ delete_insn (trace.setcc.insn);
+
+ return;
+ }
+
// Now that we have an insn which tests some reg and sets the condition
// reg before the conditional branch, try to figure out how that tested
// reg was formed, i.e. find all the insns that set the tested reg in
