We can have SAVE_MULTIPLE while we do not have REST_MULTIPLE. If the
inline restore does not restore all registers, the CFI for the save
and restore can conflict if things are shrink-wrapped.
We could restore all registers that are saved (not ideal), or emit
the CFI notes to say we did (which will work fine, but is also not
so great); instead, let's not save the registers that are unused.
Tested on powerpc64-linux {-m32,-m64}; committing to trunk.
Segher
2017-08-09 Segher Boessenkool <seg...@kernel.crashing.org>
PR target/80938
* config/rs6000/rs6000.c (rs6000_savres_strategy): Don't use
SAVE_MULTIPLE if not all the registers that saves, should be saved.
---
gcc/config/rs6000/rs6000.c | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 0f0b1ff..e8cdd25 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -24437,6 +24437,21 @@ rs6000_savres_strategy (rs6000_stack_t *info,
else if (!lr_save_p && info->first_gp_reg_save > 29)
strategy |= SAVE_INLINE_GPRS | REST_INLINE_GPRS;
+ /* We can only use save multiple if we need to save all the registers from
+ first_gp_reg_save. Otherwise, the CFI gets messed up (we save some
+ register we do not restore). */
+ if (strategy & SAVE_MULTIPLE)
+ {
+ int i;
+
+ for (i = info->first_gp_reg_save; i < 32; i++)
+ if (fixed_reg_p (i) || !save_reg_p (i))
+ {
+ strategy &= ~SAVE_MULTIPLE;
+ break;
+ }
+ }
+
/* We can only use load multiple or the out-of-line routines to
restore gprs if we've saved all the registers from
first_gp_reg_save. Otherwise, we risk loading garbage.
--
1.9.3
