[PATCH] Fix ARM constant-pool layout calculations under -falign-labels

[Roland McGrath]

Using e.g. -falign-labels=16 on ARM can confuse the constant-pool layout
code such that it places pool entries too far away from their referring
instructions.  This change seems to fix it.

I don't have a small test case, only a large one, which I haven't actually
tried to get to reproduce on any vanilla ARM target.  But the logic of the
change seems straightforward and sound.


Thanks,
Roland


2012-08-01  Roland McGrath  <mcgra...@google.com>

        * config/arm/arm.c (get_label_padding): Use align_labels as minimum.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 701ab4c..9bdb52c 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -12384,6 +12384,7 @@ get_label_padding (rtx label)
   HOST_WIDE_INT align, min_insn_size;

   align = 1 << label_to_alignment (label);
+  align = MAX (align, align_labels);
   min_insn_size = TARGET_THUMB ? 2 : 4;
   return align > min_insn_size ? align - min_insn_size : 0;
 }