* Re: Re: [BUG?] GCC inline assembler optimization issue
@ 2009-12-27 0:28 Dan Kruchinin
2009-12-28 3:22 ` Andrew Haley
0 siblings, 1 reply; 2+ messages in thread
From: Dan Kruchinin @ 2009-12-27 0:28 UTC (permalink / raw)
To: gcc-help
As I wrote earlier, memory clobber didn't help, but there is an interesting thing:
I replaced description of the third argument of spin_lock function from "rI" to "r" and it fixed my problem.
AFAIK the only one thing "I" does and that is describing my argument as a constant in range 0 - 31.
I don't understand why it so radically changes generated code.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [BUG?] GCC inline assembler optimization issue
2009-12-27 0:28 Re: [BUG?] GCC inline assembler optimization issue Dan Kruchinin
@ 2009-12-28 3:22 ` Andrew Haley
0 siblings, 0 replies; 2+ messages in thread
From: Andrew Haley @ 2009-12-28 3:22 UTC (permalink / raw)
To: gcc-help
On 12/26/2009 11:56 PM, Dan Kruchinin wrote:
> As I wrote earlier, memory clobber didn't help, but there is an interesting thing:
> I replaced description of the third argument of spin_lock function from "rI" to "r" and it fixed my problem.
> AFAIK the only one thing "I" does and that is describing my argument as a constant in range 0 - 31.
> I don't understand why it so radically changes generated code.
It doesn't. Your problem is the missing clobber on Operand 1
in the asm in spin_unlock.
Andrew.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2009-12-27 0:28 Re: [BUG?] GCC inline assembler optimization issue Dan Kruchinin
2009-12-28 3:22 ` Andrew Haley
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