Hi Andrew,
On 11 July 2018 at 15:43, Andrew Pinski <pins...@gmail.com> wrote:
> On Tue, Jul 10, 2018 at 6:35 PM Kugan Vivekanandarajah
> <kugan.vivekanandara...@linaro.org> wrote:
>>
>> Hi Andrew,
>>
>> On 11 July 2018 at 11:19, Andrew Pinski <pins...@gmail.com> wrote:
>> > On Tue, Jul 10, 2018 at 6:14 PM Kugan Vivekanandarajah
>> > <kugan.vivekanandara...@linaro.org> wrote:
>> >>
>> >> On 10 July 2018 at 23:17, Richard Biener <richard.guent...@gmail.com>
>> >> wrote:
>> >> > On Tue, Jul 10, 2018 at 3:06 PM Kugan Vivekanandarajah
>> >> > <kugan.vivekanandara...@linaro.org> wrote:
>> >> >>
>> >> >> Hi,
>> >> >>
>> >> >> Jeff told me that the recent popcount built-in detection is causing
>> >> >> kernel build issues as
>> >> >> ERROR: "__popcountsi2"
>> >> >> [drivers/net/wireless/broadcom/brcm80211/brcmfmac/brcmfmac.ko]
>> >> >> undefined!
>> >> >>
>> >> >> I could also reproduce this. AFIK, we should check if the libfunc is
>> >> >> defined while checking popcount?
>> >> >>
>> >> >> I am testing the attached RFC patch. Is this reasonable?
>> >> >
>> >> > It doesn't work that way, all targets have this libfunc in libgcc.
>> >> > This means
>> >> > the kernel has to provide it. The only thing you could do is restrict
>> >> > replacement of CALL_EXPRs (in SCEV cprop) to those the target
>> >> > natively supports.
>> >>
>> >> How about restricting it in expression_expensive_p ? Is that what you
>> >> wanted. Attached patch does this.
>> >> Bootstrap and regression testing progressing.
>> >
>> > Seems like that should go into is_inexpensive_builtin instead which
>> > is just tested right below.
>>
>> I hought about that. is_inexpensive_builtin is used in various other
>> places including some inlining decision so wasn't sure if it is the
>> right thing. Happy to change it if that is the right thing to do.
>
> I audited all of the users (and their users if it is used in a
> wrapper) and found that is_inexpensive_builtin should return false for
> this builtin if it is a function call in the end; there are other
> builtins which should be checked the similar way but I think we should
> not going to force you to do the similar thing for those builtins.
Attached patch does this. Testing is progressing. Is This OK if no regression.
Thanks,
Kugan
>
> Thanks,
> Andrew
>
>>
>> Thanks,
>> Kugan
>> >
>> > Thanks,
>> > Andrew
>> >
>> >>
>> >> Thanks,
>> >> Kugan
>> >>
>> >> >
>> >> > Richard.
>> >> >
>> >> >> Thanks,
>> >> >> Kugan
>> >> >>
>> >> >> gcc/ChangeLog:
>> >> >>
>> >> >> 2018-07-10 Kugan Vivekanandarajah <kug...@linaro.org>
>> >> >>
>> >> >> * tree-ssa-loop-niter.c (number_of_iterations_popcount): Check
>> >> >> if libfunc for popcount is available.
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 820d6c2..59cf567 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -10619,6 +10619,18 @@ is_inexpensive_builtin (tree decl)
else if (DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL)
switch (DECL_FUNCTION_CODE (decl))
{
+ case BUILT_IN_POPCOUNT:
+ case BUILT_IN_POPCOUNTL:
+ case BUILT_IN_POPCOUNTLL:
+ {
+ tree arg = TYPE_ARG_TYPES (TREE_TYPE (decl));
+ /* Check if opcode for popcount is available. */
+ if (optab_handler (popcount_optab,
+ TYPE_MODE (TREE_VALUE (arg)))
+ == CODE_FOR_nothing)
+ return false;
+ }
+ return true;
case BUILT_IN_ABS:
CASE_BUILT_IN_ALLOCA:
case BUILT_IN_BSWAP16:
@@ -10670,10 +10682,7 @@ is_inexpensive_builtin (tree decl)
case BUILT_IN_VA_COPY:
case BUILT_IN_TRAP:
case BUILT_IN_SAVEREGS:
- case BUILT_IN_POPCOUNTL:
- case BUILT_IN_POPCOUNTLL:
case BUILT_IN_POPCOUNTIMAX:
- case BUILT_IN_POPCOUNT:
case BUILT_IN_PARITYL:
case BUILT_IN_PARITYLL:
case BUILT_IN_PARITYIMAX:
diff --git a/gcc/testsuite/gcc.target/aarch64/popcount4.c
b/gcc/testsuite/gcc.target/aarch64/popcount4.c
index e69de29..ee55b2e 100644
--- a/gcc/testsuite/gcc.target/aarch64/popcount4.c
+++ b/gcc/testsuite/gcc.target/aarch64/popcount4.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized -mgeneral-regs-only" } */
+
+int PopCount (long b) {
+ int c = 0;
+
+ while (b) {
+ b &= b - 1;
+ c++;
+ }
+ return c;
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin_popcount" 0 "optimized" } } */
