[PATCH] DCE dead IFN_GOMP_SIMD_LANE

[Jakub Jelinek]

Hi!

When looking at PR59984, I've noticed that in certain cases we leave
around GOMP_SIMD_LANE calls without lhs.
This internal call is intentionally not ECF_CONST, we don't want it moved
before the loop, and the argument is magic.  But, if nothing uses it
anymore, it isn't needed.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2014-11-14  Jakub Jelinek  ja...@redhat.com

* tree-ssa.dce.c (eliminate_unnecessary_stmts): Eliminate
IFN_GOMP_SIMD_LANE without lhs as useless.

--- gcc/tree-ssa-dce.c.jj   2014-11-12 13:28:47.0 +0100
+++ gcc/tree-ssa-dce.c  2014-11-14 16:15:10.356124955 +0100
@@ -1402,6 +1402,11 @@ eliminate_unnecessary_stmts (void)
  maybe_clean_or_replace_eh_stmt (stmt, stmt);
  update_stmt (stmt);
  release_ssa_name (name);
+
+ /* GOMP_SIMD_LANE without lhs is not needed.  */
+ if (gimple_call_internal_p (stmt)
+  gimple_call_internal_fn (stmt) == IFN_GOMP_SIMD_LANE)
+   remove_dead_stmt (gsi, bb);
}
  else if (gimple_call_internal_p (stmt))
switch (gimple_call_internal_fn (stmt))

Jakub

Re: [PATCH] DCE dead IFN_GOMP_SIMD_LANE

[Jeff Law]

On 11/14/14 10:33, Jakub Jelinek wrote:

Hi!

When looking at PR59984, I've noticed that in certain cases we leave
around GOMP_SIMD_LANE calls without lhs.
This internal call is intentionally not ECF_CONST, we don't want it moved
before the loop, and the argument is magic.  But, if nothing uses it
anymore, it isn't needed.

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
trunk?

2014-11-14  Jakub Jelinek  ja...@redhat.com

* tree-ssa.dce.c (eliminate_unnecessary_stmts): Eliminate
IFN_GOMP_SIMD_LANE without lhs as useless.
OK.  I presume we don't have other functions with similar 
characteristics?  If we did, then we might want a more general interface 
or some way to tag them rather than checking for them by name in DCE.


jeff