On 09/05/16 16:08, Segher Boessenkool wrote:
Hi Christophe,
On Mon, May 09, 2016 at 03:54:26PM +0200, Christophe Lyon wrote:
After this patch, I've noticed that
gcc.target/arm/pr43920-2.c
now fails at:
/* { dg-final { scan-assembler-times "pop" 2 } } */
Before the patch, the generated code was:
[...]
pop {r3, r4, r5, r6, r7, pc}
.L4:
mov r0, #-1
.L1:
pop {r3, r4, r5, r6, r7, pc}
it is now:
[...]
.L1:
pop {r3, r4, r5, r6, r7, pc}
.L4:
mov r0, #-1
b .L1
The new version does not seem better, as it adds a branch on the path
and it is not smaller.
That looks like bb-reorder isn't doing its job? Maybe it thinks that
pop is too expensive to copy?
I think so. Filed PR71061
ARM backend is not setting the length attribute correctly, that the bb
failed copy_bb_p check.
Unfortunately I am afraid even we fixed the backend length issue, this
testcase
will keep failing, because it's specify "-Os" that some bb copy won't be
triggerd.
