Commit Graph

3 Commits

Author SHA1 Message Date
Hal Finkel ee90a223ea Support the assume_aligned function attribute
In addition to __builtin_assume_aligned, GCC also supports an assume_aligned
attribute which specifies the alignment (and optional offset) of a function's
return value. Here we implement support for the assume_aligned attribute by making
use of the @llvm.assume intrinsic.

llvm-svn: 218500
2014-09-26 05:04:30 +00:00
Hal Finkel e65e0a1bc9 Don't test really-large alignments for now
Temporarily comment out the test for really-large powers of two. This seems to
be host-sensitive for some reason... trying to fix the clang-i386-freebsd
builder.

llvm-svn: 217351
2014-09-08 00:09:15 +00:00
Hal Finkel bcc06085a8 Add __builtin_assume and __builtin_assume_aligned using @llvm.assume.
This makes use of the recently-added @llvm.assume intrinsic to implement a
__builtin_assume(bool) intrinsic (to provide additional information to the
optimizer). This hooks up __assume in MS-compatibility mode to mirror
__builtin_assume (the semantics have been intentionally kept compatible), and
implements GCC's __builtin_assume_aligned as assume((p - o) & mask == 0). LLVM
now contains special logic to deal with assumptions of this form.

llvm-svn: 217349
2014-09-07 22:58:14 +00:00