This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [PATCH] PR49799: Don't generate illegal bit field extraction instruction
Test case added.
Tested with
make check-gcc RUNTESTFLAGS="--target_board=arm-sim/thumb/arch=armv7-a
arm.exp=pr49799.c"
make check-gcc RUNTESTFLAGS="--target_board=arm-sim/arch=armv7-a
arm.exp=pr49799.c"
It fails without this patch and passes with this patch.
OK for trunk and 4.6 now?
thanks
Carrot
ChangeLog:
2011-07-28 Wei Guozhi <carrot@google.com>
PR rtl-optimization/49799
* combine.c (make_compound_operation): Check if the bit field is valid
before change it to bit field extraction.
ChangeLog:
2011-07-28 Wei Guozhi <carrot@google.com>
PR rtl-optimization/49799
* pr49799.c : New test case.
Index: gcc/combine.c
===================================================================
--- gcc/combine.c (revision 176733)
+++ gcc/combine.c (working copy)
@@ -7787,6 +7787,7 @@ make_compound_operation (rtx x, enum rtx
&& GET_CODE (lhs) == ASHIFT
&& CONST_INT_P (XEXP (lhs, 1))
&& INTVAL (rhs) >= INTVAL (XEXP (lhs, 1))
+ && INTVAL (XEXP (lhs, 1)) >= 0
&& INTVAL (rhs) < mode_width)
{
new_rtx = make_compound_operation (XEXP (lhs, 0), next_code);
Index: pr49799.c
===================================================================
--- pr49799.c (revision 0)
+++ pr49799.c (revision 0)
@@ -0,0 +1,25 @@
+/* PR rtl-optimization/49799 */
+/* { dg-do assemble } */
+/* { dg-options "-O2 -w -march=armv7-a" } */
+
+static __inline int bar(int a)
+{
+ int tmp;
+
+ if (a <= 0) a ^= 0xFFFFFFFF;
+
+ return tmp - 1;
+}
+
+void foo(short *K)
+{
+ short tmp;
+ short *pptr, P[14];
+
+ pptr = P;
+ tmp = bar(*K);
+ *pptr = (*K << tmp) >> 16;
+
+ if (*P < tmp)
+ *K++ = 0;
+}
On Thu, Jul 28, 2011 at 4:04 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Thu, Jul 28, 2011 at 03:38:07PM +0800, Carrot Wei wrote:
>> OK for trunk and 4.6?
>>
>> ChangeLog:
>> 2011-07-28 ?Wei Guozhi ?<carrot@google.com>
>>
>> ? ? ? ? PR rtl-optimization/49799
>> ? ? ? ? * combine.c (make_compound_operation): Check if the bit field is valid
>> ? ? ? ? before change it to bit field extraction.
>
> Looks good to me, handling SHIFT_COUNT_TRUNCATED here isn't IMHO necessary
> and the checking whether shift count is in the right range matches other rtx
> simplifications (e.g. in simplify-rtx.c).
> Though, you should add a testcase, probably
> /* PR rtl-optimization/49799 */
> /* { dg-do assemble } */
> /* { dg-options "-O2 -w" } */
>
> plus not sure if for arm you don't want to force this -march=armv7-a
> into dg-options too or just leave it as is.
>
> ? ? ? ?Jakub
>