[Bug tree-optimization/123153] [16 regression] gcc/tree-vect-loop-manip.cc:1979: -Wliteral-conversion

[dcb314 at hotmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123153

--- Comment #1 from David Binderman <dcb314 at hotmail dot com> ---
Here is some C++ code that demonstrates the problem:

extern void f( int);

void g()
{
    f( 0.5);
}

gcc says nothing:

Alphasrc $ ~/gcc/results/bin/gcc -c -g -O2 -Wall -Wextra -pedantic  dec16c.cc
Alphasrc $

Here is clang finding the problem:

Alphasrc $ clang++ -c dec16c.cc
dec16c.cc:6:5: warning: implicit conversion from 'double' to 'int' changes
value from 0.5 to 0 [-Wliteral-conversion]
    6 |         f( 0.5);
      |         ~  ^~~
1 warning generated.

Only with some little known encouragement can gcc be persuaded
to find the problem:

Alphasrc $ ~/gcc/results/bin/gcc -c -g -O2 -Wall -Wextra -pedantic -Wconversion
dec16c.cc
dec16c.cc: In function ‘void g()’:
dec16c.cc:6:12: warning: conversion from ‘double’ to ‘int’ changes value from
‘5.0e-1’ to ‘0’ [-Wfloat-conversion]
    6 |         f( 0.5);
      |            ^~~
Alphasrc $