Commit Graph

6 Commits

Author SHA1 Message Date
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
d9fb712403 Teach LSR sink to sink the immediate portion of the common expression back into uses if they fit in address modes of all the uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65215 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-21 02:06:47 +00:00
Evan Cheng
073c5b721d Don't mask the isel bug.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47018 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-12 19:11:29 +00:00
Evan Cheng
65b2e3df0d Fix some test cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46998 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-12 07:22:46 +00:00
Dale Johannesen
0bd5fcf49f This was failing on Darwin, which defaults to PIC;
no lea was generated.  I think this follows the intent.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43312 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-24 20:58:14 +00:00
Dan Gohman
02e4fa7d5f Strength reduction improvements.
- Avoid attempting stride-reuse in the case that there are users that
   aren't addresses. In that case, there will be places where the
   multiplications won't be folded away, so it's better to try to
   strength-reduce them.

 - Several SSE intrinsics have operands that strength-reduction can
   treat as addresses. The previous item makes this more visible, as
   any non-address use of an IV can inhibit stride-reuse.

 - Make ValidStride aware of whether there's likely to be a base
   register in the address computation. This prevents it from thinking
   that things like stride 9 are valid on x86 when the base register is
   already occupied.

Also, XFAIL the 2007-08-10-LEA16Use32.ll test; the new logic to avoid
stride-reuse elimintes the LEA in the loop, so the test is no longer
testing what it was intended to test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43231 91177308-0d34-0410-b5e6-96231b3b80d8
2007-10-22 20:40:42 +00:00