Commit Graph

2 Commits

Author SHA1 Message Date
Tim Northover 64ec0ff433 X86: use sub-register sequences for MOV*r0 operations
Instead of having a bunch of separate MOV8r0, MOV16r0, ... pseudo-instructions,
it's better to use a single MOV32r0 (which will expand to "xorl %reg, %reg")
and obtain other sizes with EXTRACT_SUBREG and SUBREG_TO_REG. The encoding is
smaller and partial register updates can sometimes be avoided.

Until recently, this sequence was a barrier to rematerialization though. That
should now be fixed so it's an appropriate time to make the change.

llvm-svn: 182928
2013-05-30 13:19:42 +00:00
Eli Bendersky 24a36eb331 This patch teaches x86 fast-isel to generate the native div/idiv instructions
for the sdiv/srem/udiv/urem bitcode instructions.  This is done for the i8,
i16, and i32 types, as well as i64 for the x86_64 target.

Patch by Jim Stichnoth

llvm-svn: 179715
2013-04-17 20:10:13 +00:00