Commit Graph

3 Commits

Author SHA1 Message Date
Dale Johannesen
c1acc3f764 Reverse a loop that is counting up to a maximum to
count down to 0 instead, under very restricted
circumstances.  Adjust 4 testcases in which this
optimization fires.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71439 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-11 17:15:42 +00:00
Dan Gohman
2d1be87ee4 Expand GEPs in ScalarEvolution expressions. SCEV expressions can now
have pointer types, though in contrast to C pointer types, SCEV
addition is never implicitly scaled. This not only eliminates the
need for special code like IndVars' EliminatePointerRecurrence
and LSR's own GEP expansion code, it also does a better job because
it lets the normal optimizations handle pointer expressions just
like integer expressions.

Also, since LLVM IR GEPs can't directly index into multi-dimensional
VLAs, moving the GEP analysis out of client code and into the SCEV
framework makes it easier for clients to handle multi-dimensional
VLAs the same way as other arrays.

Some existing regression tests show improved optimization.
test/CodeGen/ARM/2007-03-13-InstrSched.ll in particular improved to
the point where if-conversion started kicking in; I turned it off
for this test to preserve the intent of the test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69258 91177308-0d34-0410-b5e6-96231b3b80d8
2009-04-16 03:18:22 +00:00
Evan Cheng
752272a5e5 Implement PR3495: local spiller optimization. The local spiller can now keep availability information over BB boundaries. It visits BB's in depth first order. After visiting a BB if it find a successor which has a single predecessor it visits the successor next without clearing the availability information. This allows the successor to omit reloads or change them into copies.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64298 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-11 08:24:21 +00:00