tree a1a33557d09b6f8a8c9b36ca2b57f38319f3b39b
parent 3a84c8e25251b961bf91f713b5175f834aaa7bef
author Nicolas Capens <capn@google.com> 1626208600 -0400
committer Nicolas Capens <nicolascapens@google.com> 1626726552 +0000

Increase Subzero x86-64 stack alignment to 16

The SystemV x64 ABI requires that "The stack is 16-byte aligned just
before the call instruction is called."

The Microsoft x64 ABI states that "The stack will always be maintained
16-byte aligned, except within the prolog (for example, after the return
address is pushed), and except where indicated in Function Types for a
certain class of frame functions." The latter refers to functions which
do not call other functions but are not leaf functions (i.e. they may be
called externally, or allocate additional stack space).

This change fixes the calling convention and improves performance for
spilled 128-bit vectors.

Bug: b/193550986
Change-Id: If26600b701359da996b288a86ec92e07132913b2
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/55810
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Sean Risser <srisser@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>