From: Nick Desaulniers <ndesaulniers@google.com> Date: 2018-11-02 16:56:41
On Thu, Nov 1, 2018 at 8:37 PM Joel Stanley [off-list ref] wrote:
make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- ppc44x_defconfig
make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-
...
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
FP_ADD_D(R, T, B);
^~~~~~~~~~~~~~~~~
./include/math-emu/double.h:110:27: note: expanded from macro 'FP_ADD_D'
#define FP_ADD_D(R,X,Y) _FP_ADD(D,2,R,X,Y)
^~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:367:34: note: expanded from macro '_FP_ADD'
#define _FP_ADD(fs, wc, R, X, Y) _FP_ADD_INTERNAL(fs, wc, R, X, Y, '+')
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:264:4: note: expanded from macro '_FP_ADD_INTERNAL'
_FP_FRAC_ADD_##wc(R, X, Y); \
^~~~~~~~~~~~~~~~~~~~~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
^^^ Hi Joel, would you mind recompiling with
`-fmacro-backtrace-limit=0` hacked in and including the full
backtrace? I'm curious if there's a more appropriate fix, but can't
tell where the inline asm is that clang is complaining about.
quoted hunk
./include/math-emu/op-2.h:94:27: note: expanded from macro '_FP_FRAC_ADD_2'
__FP_FRAC_ADD_2(R##_f1, R##_f0, X##_f1, X##_f0, Y##_f1, Y##_f0)
~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Link: https://github.com/ClangBuiltLinux/linux/issues/260
Signed-off-by: Joel Stanley <joel@jms.id.au>
---
arch/powerpc/math-emu/Makefile | 4 ++++
1 file changed, 4 insertions(+)
On Fri, Nov 02, 2018 at 02:07:13PM +1030, Joel Stanley wrote:
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
(It is spelled lvalue).
*All* of extended asm is a GNU extension, what is clang trying to say here?
Confused :-)
Segher
From: Nick Desaulniers <ndesaulniers@google.com> Date: 2018-11-02 17:41:54
On Fri, Nov 2, 2018 at 10:34 AM Segher Boessenkool
[off-list ref] wrote:
On Fri, Nov 02, 2018 at 02:07:13PM +1030, Joel Stanley wrote:
quoted
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
(It is spelled lvalue).
*All* of extended asm is a GNU extension, what is clang trying to say here?
Confused :-)
Isn't the result of a cast a temporary value? Probably just need to
move the case out of the inline asm block to a separate statement.
Having the full backtrace should help.
--
Thanks,
~Nick Desaulniers
On Fri, Nov 02, 2018 at 10:38:36AM -0700, Nick Desaulniers wrote:
On Fri, Nov 2, 2018 at 10:34 AM Segher Boessenkool
[off-list ref] wrote:
quoted
On Fri, Nov 02, 2018 at 02:07:13PM +1030, Joel Stanley wrote:
quoted
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
(It is spelled lvalue).
*All* of extended asm is a GNU extension, what is clang trying to say here?
Confused :-)
Isn't the result of a cast a temporary value? Probably just need to
move the case out of the inline asm block to a separate statement.
Having the full backtrace should help.
The kernel's sfp-machine.h has casts in lvalues, inside macros. All such
casts seem to be casts to compatible types (and if not, it probably won't
work with GCC either).
Segher
From: Joel Stanley <joel@jms.id.au> Date: 2018-11-12 11:36:33
On Sat, 3 Nov 2018 at 03:24, Nick Desaulniers [off-list ref] wrote:
On Thu, Nov 1, 2018 at 8:37 PM Joel Stanley [off-list ref] wrote:
quoted
make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu- ppc44x_defconfig
make CC=clang-8 ARCH=powerpc CROSS_COMPILE=powerpc-linux-gnu-
...
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
FP_ADD_D(R, T, B);
^~~~~~~~~~~~~~~~~
./include/math-emu/double.h:110:27: note: expanded from macro 'FP_ADD_D'
#define FP_ADD_D(R,X,Y) _FP_ADD(D,2,R,X,Y)
^~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:367:34: note: expanded from macro '_FP_ADD'
#define _FP_ADD(fs, wc, R, X, Y) _FP_ADD_INTERNAL(fs, wc, R, X, Y, '+')
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:264:4: note: expanded from macro '_FP_ADD_INTERNAL'
_FP_FRAC_ADD_##wc(R, X, Y); \
^~~~~~~~~~~~~~~~~~~~~~~~~~
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
^^^ Hi Joel, would you mind recompiling with
`-fmacro-backtrace-limit=0` hacked in and including the full
backtrace? I'm curious if there's a more appropriate fix, but can't
tell where the inline asm is that clang is complaining about.
Sure. Here's the full backtrace:
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove
the cast or build with -fheinous-gnu-extensions
FP_ADD_D(R, T, B);
^~~~~~~~~~~~~~~~~
./include/math-emu/double.h:110:27: note: expanded from macro 'FP_ADD_D'
#define FP_ADD_D(R,X,Y) _FP_ADD(D,2,R,X,Y)
^~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:367:34: note: expanded from macro '_FP_ADD'
#define _FP_ADD(fs, wc, R, X, Y) _FP_ADD_INTERNAL(fs, wc, R, X, Y, '+')
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./include/math-emu/op-common.h:274:4: note: expanded from macro
'_FP_ADD_INTERNAL'
_FP_FRAC_SUB_##wc(R, X, Y); \
^~~~~~~~~~~~~~~~~~~~~~~~~~
<scratch space>:268:1: note: expanded from here
_FP_FRAC_SUB_2
^
./include/math-emu/op-2.h:97:19: note: expanded from macro '_FP_FRAC_SUB_2'
__FP_FRAC_SUB_2(R##_f1, R##_f0, X##_f1, X##_f0, Y##_f1, Y##_f0)
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
<scratch space>:269:1: note: expanded from here
R_f1
^
./arch/powerpc/include/asm/sfp-machine.h:283:27: note: expanded from
macro 'sub_ddmmss'
: "=r" ((USItype)(sh)), \
~~~~~~~~~~^~~
On Mon, Nov 12, 2018 at 10:03:34PM +1030, Joel Stanley wrote:
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove
the cast or build with -fheinous-gnu-extensions
This was fixed in GCC over 16 years ago ( https://gcc.gnu.org/r56600 ),
and in GMP (where it comes from) presumably before that.
There are many projects around which still have old GMP snippets in
them. Like, the Linux kernel for powerpc, or GCC for x86!
Segher
From: Nick Desaulniers <ndesaulniers@google.com> Date: 2018-11-12 19:19:31
On Mon, Nov 12, 2018 at 3:33 AM Joel Stanley [off-list ref] wrote:
quoted
On Thu, Nov 1, 2018 at 8:37 PM Joel Stanley [off-list ref] wrote:
quoted
arch/powerpc/math-emu/fnmsub.c:46:2: error: invalid use of a cast in a
inline asm context requiring an l-value: remove the cast or build with
-fheinous-gnu-extensions
Eek, I can of think that add_ssaaaa(), sub_ddmmss(), and umul_ppmm()
should be rewritten from the form:
asm("..." : "=r" (USItype)(arg) : ...);
to the form:
USItype temp = (USItype) arg;
asm("..." : "=r" (temp) : ...);
arg = (typeof(arg)) temp;
Rather than the flag being added.
--
Thanks,
~Nick Desaulniers