PR78590 shows a problem in change_zero_ext, where we change a zero_extend
of a subreg to a logical and. We should only do this if the thing we are
taking the subreg of is a scalar integer, otherwise we will take a subreg
of (e.g.) a float in a different size, which is nonsensical and hits an
assert.
Tested on powerpc64-linux; committing to trunk.
Segher
2016-11-30 Segher Boessenkool <seg...@kernel.crashing.org>
PR rtl-optimization/78590
* combine.c (change_zero_ext): Transform zero_extend of subregs only
if the subreg_reg is a scalar integer mode.
---
gcc/combine.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/gcc/combine.c b/gcc/combine.c
index 5696eea9..fd33a4d 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -11285,6 +11285,7 @@ change_zero_ext (rtx pat)
else if (GET_CODE (x) == ZERO_EXTEND
&& SCALAR_INT_MODE_P (mode)
&& GET_CODE (XEXP (x, 0)) == SUBREG
+ && SCALAR_INT_MODE_P (GET_MODE (SUBREG_REG (XEXP (x, 0))))
&& !paradoxical_subreg_p (XEXP (x, 0))
&& subreg_lowpart_p (XEXP (x, 0)))
{
--
1.9.3
