C++ PATCHes for bootstrap/68346, 68361

[Jason Merrill]

On 11/17/2015 01:15 PM, Jason Merrill wrote:
> A couple of bootstrap issues on some targets:
>
> 68346: My earlier change to avoid folding the arguments to
> warn_tautological_cmp wasn't quite right, either.  This patch folds
> within the function, at the place where we are interested in a constant
> value.

I also noticed that we weren't leaving any indication of the cast in the 
trees, which also would have avoided the warning.  With delayed folding 
there really should be one, so I added it.  Which caused a crash in the 
LITERAL_ZERO_P code.  Which is obsolete now, so I've removed it.  Which 
required my code to immediately fold negation of a constant to avoid 
folding -0 into 0; while I was looking at that I also limited it to 
folding only when the numeric literal immediately follows the -.

Tested x86_64-pc-linux-gnu, applying to trunk.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: 68346-2.patch
Type: text/x-patch
Size: 825 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20151117/faaceaef/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: lit-zero.patch
Type: text/x-patch
Size: 6019 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20151117/faaceaef/attachment-0001.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: neg-fold.patch
Type: text/x-patch
Size: 2319 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20151117/faaceaef/attachment-0002.bin>