[Bug c++/40752] -Wconversion generates false warnings for operands not larger than target type

["chengniansun at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40752

--- Comment #25 from Chengnian Sun <chengniansun at gmail dot com> ---
Today I encountered a similar case as follows. The conversion warning by gcc is
not true as right-shifting an unsigned short decreases the value. 

BTW clang does not emit warnings for this code snippet. 


$: cat s1.c
unsigned short fn(unsigned short a, int right) {
  return a >> right;
}
$: gcc-trunk -c -Wconversion s1.c
s1.c: In function ‘fn’:
s1.c:2:3: warning: conversion to ‘short unsigned int’ from ‘int’ may alter its
value [-Wconversion]
   return a >> right;
   ^
$: clang-trunk -c -Wconversion s1.c
$:
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Subject: [Bug c++/60113] Internal compiler error
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id`113

--- Comment #2 from lmat <dartmetrash at gmail dot com> ---
Created attachment 32090
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id2090&actioníit
Bug report including command line output.

My apologies! I was quite sure I had attached it, but I see quite plainly that
I had failed! It appears that my upload was too big. I've divided it up using

split --lines 35000 ...

which creates three files.