[PATCH] Do not remove labels with LABEL_PRESERVE_P
Ilya Enkovich
enkovich.gnu@gmail.com
Fri Sep 19 19:36:00 GMT 2014
Hi,
During my work on enabling pseudo PIC register I've found that cfg cleaunp may remove lables with LABEL_PRESERVE_P set to 1. In my case I generated SET_RIP during expand pass and cfg cleanup removed label it used as an operand. Below is a patch that fixes it. It is not actually required for our latest PIC related patch but still seems to make sense.
Bootstrapped and tested on linux-x86_64.
Thanks,
Ilya
--
2014-09-19 Ilya Enkovich <ilya.enkovich@intel.com>
* cfgcleanup.c (try_optimize_cfg): Do not remove label
with LABEL_PRESERVE_P flag set.
diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index a008168..9325ea0 100644
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -2701,6 +2701,7 @@ try_optimize_cfg (int mode)
&& (single_pred_edge (b)->flags & EDGE_FALLTHRU)
&& !(single_pred_edge (b)->flags & EDGE_COMPLEX)
&& LABEL_P (BB_HEAD (b))
+ && !LABEL_PRESERVE_P (BB_HEAD (b))
/* If the previous block ends with a branch to this
block, we can't delete the label. Normally this
is a condjump that is yet to be simplified, but
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