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Date: Wed, 23 Apr 2003 10:36:00 -0000
From: Jie Zhang <zhangjie@magima.com.cn>
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To:  gcc@gcc.gnu.org
Subject: An error of gcc-ss-20030303
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The following code is copied from spinlock.c in uClibc (after 
preprocessing and 'inline' after static removed):

static void __pthread_release(int * spinlock)
{
  asm ("" : : : "memory");
  *spinlock = 0;
  __asm __volatile ("" : "=m" (*spinlock) : "0" (*spinlock));
}

When compiled using gcc-3.0.2, no error is reported. But gcc-3.2 and 
gcc-ss-20030303 report the follwing error:

t.c: In function `__pthread_release':
t.c:5: inconsistent operand constraints in an `asm'

I dump the rtl using -dr and find that gcc-3.0.2 uses a pseudo register 
to hold the address of 'spinlock' and the output operand and input 
operand of __asm__ use the same register. But gcc-ss-20030303 uses two 
pseudo registers for the output operand and input operand of __asm__ 
respectively, both pseudo registers hold the same value -- the address 
of 'spinlock'. Then when checking the constraints, gcc reports the error.

Is it a bug of gcc-3.2.x and gcc-3.3? Or the above __asm__ usage is 
wrong in gcc-3.2.x and gcc-3.3? I think gcc-3.0.2 is right?

- Jie