POWER8 inline assembly clobbers

[Anton Blanchard]

OpenBLAS fails to build on a recent ppc64le toolchain because of issues with inline assembly clobbers, eg:

../kernel/power/scopy_microk_power8.c:57:2: error: PIC register clobbered by ‘%2’ in ‘asm’

The clobbers do specify r2:

        : "cr0", "%0", "%2" , "%1", "memory"

Is there a reason we are we specifying r0, r2 and r1 in the clobber list?

Anton

[Werner Saar]

Hi,

%0, %1 and %2 are not the register but the inputs i, x1 and y1.

Best regards
Werner

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[Anton Blanchard]

On Wednesday, May 11, 2016 at 2:29:06 PM UTC+10, Werner Saar wrote:

Hi,

%0, %1 and %2 are not the register but the inputs i, x1 and y1.

Your inline assembly is incorrect, it does not do that. In fact OpenBLAS will not

build on recent gcc versions because of this error.

You need to add constraints to the arguments, as an example:

        :

          "+&r" (i),    // 0    

          "+&r" (y1),   // 1

          "+&r" (x1),   // 2

          "+&r" (y2),   // 3

          "+&r" (x2),   // 4

        :

          "r" (16),     // 5

          "r" (32),     // 6

          "r" (48),     // 7

          "r" (64),     // 8

          "r" (80),     // 9

          "r" (96),     // 10

          "r" (112)     // 11

        : "cr0", "memory"

        );

[Alan Modra]

I've fixed a bunch of issues in the attached patch.  Please take a look.

[Alan Modra]

Revised patch, correcting all power8 asm().  The .S files also contain errors, not fixed by this patch.