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| author | Dan Gohman <gohman@apple.com> | 2008-10-17 01:33:43 +0000 |
|---|---|---|
| committer | Dan Gohman <gohman@apple.com> | 2008-10-17 01:33:43 +0000 |
| commit | 5a5e6e9896e813ea178f791db51d6dde04dc0b61 (patch) | |
| tree | 718d542a3b0cf7a6c76944afed13d26afbb6a12f /win32/clang.sln | |
| parent | 921581d2d000e0aa882f9dee8a104ef8a4b07e72 (diff) | |
| download | external_llvm-5a5e6e9896e813ea178f791db51d6dde04dc0b61.zip external_llvm-5a5e6e9896e813ea178f791db51d6dde04dc0b61.tar.gz external_llvm-5a5e6e9896e813ea178f791db51d6dde04dc0b61.tar.bz2 | |
Fun x86 encoding tricks: when adding an immediate value of 128,
use a SUB instruction instead of an ADD, because -128 can be
encoded in an 8-bit signed immediate field, while +128 can't be.
This avoids the need for a 32-bit immediate field in this case.
A similar optimization applies to 64-bit adds with 0x80000000,
with the 32-bit signed immediate field.
To support this, teach tablegen how to handle 64-bit constants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57663 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'win32/clang.sln')
0 files changed, 0 insertions, 0 deletions