From: David Miller <da...@redhat.com>
Date: Fri, 16 Nov 2012 00:33:05 -0500 (EST)
> From: Richard Sandiford <rdsandif...@googlemail.com>
> Date: Mon, 29 Oct 2012 10:14:53 +0000
>
>> ...given that the code is like you say written:
>>
>> if (SHIFT_COUNT_TRUNCATED)
>> {
>> if (CONST_INT_P (op1)
>> ...
>> else if (GET_CODE (op1) == SUBREG
>> && subreg_lowpart_p (op1)
>> && INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (op1))))
>> op1 = SUBREG_REG (op1);
>> }
>>
>> INTEGRAL_MODE_P (GET_MODE (op1)) might be better than an explicit
>> VECTOR_MODE_P check. The code really doesn't make sense for anything
>> other than integers.
>>
>> (It amounts to the same thing in practice, of course...)
>
> Agreed, I've just committed the following. Thanks!
>
> ====================
> Fix gcc.c-torture/compile/pr53410-2.c on sparc.
>
> * expmed.c (expand_shift_1): Don't strip non-integral SUBREGs.
This is broken on sparc again, although I'm confused about how this
has happened.
The suggestion was to use INTEGRAL_MODE_P as the test, so what's there
in expand_shift_1() is:
else if (GET_CODE (op1) == SUBREG
&& subreg_lowpart_p (op1)
&& INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (op1)))
&& INTEGRAL_MODE_P (GET_MODE (op1)))
op1 = SUBREG_REG (op1);
but INTEGRAL_MODE_P accepts vectors. This is really confusing because
I was absolutely sure I re-ran the test case with the fix I committed
and it didn't crash any more.
Maybe what we really mean to do here is check both op1 and SUBREG_REG
(op1) against SCALAR_INT_MODE_P instead of INTEGRAL_MODE_P?
Something like this:
gcc/
2013-02-12 David S. Miller <da...@davemloft.net>
* expmed.c (expand_shift_1): Only strip scalar integer subregs.
diff --git a/gcc/expmed.c b/gcc/expmed.c
index 4a6ddb0..954a360 100644
--- a/gcc/expmed.c
+++ b/gcc/expmed.c
@@ -2116,8 +2116,8 @@ expand_shift_1 (enum tree_code code, enum machine_mode
mode, rtx shifted,
% GET_MODE_BITSIZE (mode));
else if (GET_CODE (op1) == SUBREG
&& subreg_lowpart_p (op1)
- && INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (op1)))
- && INTEGRAL_MODE_P (GET_MODE (op1)))
+ && SCALAR_INT_MODE_P (GET_MODE (SUBREG_REG (op1)))
+ && SCALAR_INT_MODE_P (GET_MODE (op1)))
op1 = SUBREG_REG (op1);
}
