tree 489b9c4b84490310f360e205a0ce9567fec11527
parent 558540feea2ad57e9b8daecce1cb522df7d9266a
author Nicolas Capens <capn@google.com> 1598967917 -0400
committer Nicolas Capens <nicolascapens@google.com> 1598992821 +0000

Fix undefined behavior in minifloat conversion

Shifting a 32-bit value by 32 or more is undefined behavior in C++. This
previously happened in this code when converting a 32-bit float value to
an 11- or 10-bit minifloat which is too small to be represented as a
denormal, and should produce 0 instead.

Instead of going through this arithmetic for denormals, just test
whether the input value is too small to produce a valid denormal, and
return 0 instead.

Bug: chromium:1117433
Change-Id: I8149996fb6d66d328db45725c4cdb81dc7826a10
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/48069
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>