As Jakub found, after my recent combine patch at least on x86 problems
show up with RTL checking enabled. This is because the I2 generated
by a successful instruction combination can write not only a register
but it can also write a paradoxical subreg of one.
This fixes it.
Tested on powerpc64-linux {-m64,-m32} and on x86_64-linux {-m64,-m32},
with --enable-checking=yes,rtl. Committing it now.
Segher
2018-02-16 Segher Boessenkool <seg...@kernel.crashing.org>
* combine.c (try_combine): When adjusting LOG_LINKS for the destination
that moved to I2, also allow destinations that are a paradoxical
subreg (instead of a normal reg).
---
gcc/combine.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/gcc/combine.c b/gcc/combine.c
index c386f3a..cd4aaa4 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -4379,7 +4379,12 @@
if (GET_CODE (x) == PARALLEL)
x = XVECEXP (newi2pat, 0, 0);
- unsigned int regno = REGNO (SET_DEST (x));
+ /* It can only be a SET of a REG or of a paradoxical SUBREG of a REG. */
+ x = SET_DEST (x);
+ if (paradoxical_subreg_p (x))
+ x = SUBREG_REG (x);
+
+ unsigned int regno = REGNO (x);
bool done = false;
for (rtx_insn *insn = NEXT_INSN (i3);
--
1.8.3.1
