Hello,
this patch fixes PR target/70168, a wrong code generation problem
caused by rs6000_expand_atomic_compare_and_swap not properly handling
the case where changing retval clobbers newval due to a register overlap.
Tested with no regressions on powerpc64le-linux on mainline
and gcc-5-branch.
OK for both?
Bye,
Ulrich
ChangeLog:
PR target/70168
* config/rs6000/rs6000.c (rs6000_expand_atomic_compare_and_swap):
Handle overlapping retval and newval.
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c (revision 234119)
+++ gcc/config/rs6000/rs6000.c (working copy)
@@ -20740,6 +20740,9 @@
if (mode != TImode && !reg_or_short_operand (oldval, mode))
oldval = copy_to_mode_reg (mode, oldval);
+ if (reg_overlap_mentioned_p (retval, newval))
+ newval = copy_to_reg (newval);
+
mem = rs6000_pre_atomic_barrier (mem, mod_s);
label1 = NULL_RTX;
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
