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Re: PING: new pass to warn on questionable uses of alloca() and VLAs


On 10/19/2016 09:32 AM, Aldy Hernandez wrote:
On 10/19/2016 09:16 AM, Eric Botcazou wrote:
m68k-suse-linux

visium-elf too.


The attached patch fixes the failures on m68k-suse-linux, visium-elf,
and arm-eabi.

There were a few problems.

One problem is that on lp64 targets (where sizeof(size_t) !=
sizeof(int)), the warning is slightly different-- and rightly so.  I
have updated the test to handle both warnings on the respective targets.

The other problem is that the following snippet is incorrectly warning
on 32-bit targets:

  if (n > 0 && n < 2000)
    p = __builtin_alloca (n);

Looking at the gimple it seems like another case of VRP failing to give
any range information whatsoever.  I have xfailed it as another case
where Andrew's upcoming work should theoretically fix this.  The test is
fine on 64-bit targets.

Can y'all double check it on your respective targets as I only have a
crude cross build?
OK for the trunk whenever you're ready.

jeff


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