So, the story of this very small patch starts with me adding patterns
for ppc instructions bdz[tf] and bdnz[tf] such as this:
[(set (pc)
(if_then_else
(and
(ne (match_operand:P 1 "register_operand" "c,*b,*b,*b")
(const_int 1))
(match_operator 3 "branch_comparison_operator"
[(match_operand 4 "cc_reg_operand" "y,y,y,y")
(const_int 0)]))
(label_ref (match_operand 0))
(pc)))
(set (match_operand:P 2 "nonimmediate_operand" "=1,*r,m,*d*wi*c*l")
(plus:P (match_dup 1)
(const_int -1)))
(clobber (match_scratch:P 5 "=X,X,&r,r"))
(clobber (match_scratch:CC 6 "=X,&y,&y,&y"))
(clobber (match_scratch:CCEQ 7 "=X,&y,&y,&y"))]
However when this gets to the loop_doloop pass, we get an assert fail
in iv_number_of_iterations():
gcc_assert (COMPARISON_P (condition));
This is happening because this branch insn tests two things ANDed
together so the and is at the top of the expression, not a comparison.
This condition is extracted from the insn by get_condition() which is
pretty straightforward, and which calls canonicalize_condition() before
returning it. Now, one could put a test for a jump condition that is
not a conditional test in here but the comment for
canonicalize_condition() says:
(1) The code will always be a comparison operation (EQ, NE, GT, etc.).
So, this patch adds a test at the end that just returns 0 if the return
rtx is not a comparison. As it happens, doloop conversion is not needed
here because I'm already generating rtl for a branch-decrement counter
based loop.
If there is a better way to go about this please let me know and I'll
revise/retest.
Bootstrap and regtest pass on ppc64le and x86_64. Ok for trunk?
Thanks,
Aaron
2017-11-15 Aaron Sawdey <acsaw...@linux.vnet.ibm.com>
* rtlanal.c (canonicalize_condition): Return 0 if final rtx
does not have a conditional at the top.
--
Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com
050-2/C113 (507) 253-7520 home: 507/263-0782
IBM Linux Technology Center - PPC ToolchainIndex: gcc/rtlanal.c
===================================================================
--- gcc/rtlanal.c (revision 254553)
+++ gcc/rtlanal.c (working copy)
@@ -5623,7 +5623,11 @@
if (CC0_P (op0))
return 0;
- return gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
+ /* We promised to return a comparison. */
+ rtx ret = gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
+ if (COMPARISON_P (ret))
+ return ret;
+ return 0;
}
/* Given a jump insn JUMP, return the condition that will cause it to branch
