I needed to introduce a local label in this pattern because output_cbranch put
out a second instruction
in the long branch case. This fixes the issue but there are a couple ways this
could be improved:
* output_cbranch() is passed the original insn and assumes from that that the
branch is a long
branch. However this is incorrect because we are just branching to a local
label we know is only
a few instructions away. If there is a way to fix this, an unnecessary branch
could be eliminated.
* While the long branch case of this pattern needs to work, the real problem is
that part of
the code emitted by the memcmp expansion is being treated as cold code and
moved to the end of
the function. Ideally all of this code should stay together. I suspect I need
to make some kind
of branch frequency notation for this to happen.
Regstrap passes on ppc64le power7/8/9, ok for trunk and backport to 8?
Thanks!
2019-02-02 Aaron Sawdey <acsaw...@linux.ibm.com>
* config/rs6000/rs6000.md (<bd>tf_<mode>): generate a local label
for the long branch case.
Index: gcc/config/rs6000/rs6000.md
===================================================================
--- gcc/config/rs6000/rs6000.md (revision 268403)
+++ gcc/config/rs6000/rs6000.md (working copy)
@@ -12639,8 +12639,8 @@
else
{
static char seq[96];
- char *bcs = output_cbranch (operands[3], "$+8", 1, insn);
- sprintf(seq, "<bd_neg> $+12\;%s;b %%l0", bcs);
+ char *bcs = output_cbranch (operands[3], ".L%=", 1, insn);
+ sprintf(seq, "<bd_neg> .L%%=\;%s\;b %%l0\;.L%%=:", bcs);
return seq;
}
}
--
Aaron Sawdey, Ph.D. acsaw...@linux.vnet.ibm.com
050-2/C113 (507) 253-7520 home: 507/263-0782
IBM Linux Technology Center - PPC Toolchain
