llvm-project

Commit Graph

Author	SHA1	Message	Date
Owen Anderson	f4b1a5bdc4	When adding the carry bit to another value on X86, exploit the fact that the carry-materialization (sbbl x, x) sets the registers to 0 or ~0. Combined with two's complement arithmetic, we can fold the intermediate AND and the ADD into a single SUB. This fixes <rdar://problem/8449754>. llvm-svn: 114460	2010-09-21 18:41:19 +00:00

Author

SHA1

Message

Date

Owen Anderson

f4b1a5bdc4

When adding the carry bit to another value on X86, exploit the fact that the carry-materialization

(sbbl x, x) sets the registers to 0 or ~0.  Combined with two's complement arithmetic, we can fold
the intermediate AND and the ADD into a single SUB.

This fixes <rdar://problem/8449754>.

llvm-svn: 114460

2010-09-21 18:41:19 +00:00

1 Commits