| Message ID | BLU179-W725347FDF7F2042C5A2E0EB6DF0@phx.gbl |
|---|---|
| State | New |
| Headers | show |
On May 7, 2015 6:27:28 PM GMT+02:00, Aditya K <hiraditya@msn.com> wrote: >Hi, >I refactored number_of_iterations_exit a little bit. I hope it is >helpful. >The idea is to move the call to function dominated_by_p after some >sanity checks so as to avoid call to it. The call is very cheap though. Do you have data that shows it often passes when the later checks fail? Richard. > >Thanks, >-Aditya > > >2015-05-07 Aditya Kumar <hiraditya@msn.com> > > * tree-ssa-loop-niter.c (number_of_iterations_exit): Move call >to dominated_by_p later in the function. > >diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c >index 042f8df..3d49bb8 100644 >--- a/gcc/tree-ssa-loop-niter.c >+++ b/gcc/tree-ssa-loop-niter.c >@@ -1959,11 +1959,6 @@ number_of_iterations_exit (struct loop *loop, >edge exit, > affine_iv iv0, iv1; > bool safe; > >- safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); >- >- if (every_iteration && !safe) >- return false; >- > niter->assumptions = boolean_false_node; > last = last_stmt (exit->src); > if (!last) >@@ -1972,6 +1967,11 @@ number_of_iterations_exit (struct loop *loop, >edge exit, > if (!stmt) > return false; > >+ safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); >+ >+ if (every_iteration && !safe) >+ return false; >+ > /* We want the condition for staying inside loop. */ > code = gimple_cond_code (stmt); > if (exit->flags & EDGE_TRUE_VALUE) > >
---------------------------------------- > Subject: Re: Patch: Refactor number_of_iterations_exit > From: richard.guenther@gmail.com > Date: Thu, 7 May 2015 19:47:37 +0200 > To: hiraditya@msn.com; gcc-patches@gcc.gnu.org > > On May 7, 2015 6:27:28 PM GMT+02:00, Aditya K <hiraditya@msn.com> wrote: >>Hi, >>I refactored number_of_iterations_exit a little bit. I hope it is >>helpful. >>The idea is to move the call to function dominated_by_p after some >>sanity checks so as to avoid call to it. > > The call is very cheap though. Do you have data that shows it often passes when the later checks fail? I don't have any data. I was going through this code and realized that when last_stmt(exit->src) would fail or when the last_stmt is not a conditional it would be pointless to find if exit->src dominates loop->latch (which would be true for most simple loops, but then most simple loops would have conditionals as last statements. So I'm not very sure about this.) -Aditya > > Richard. > >> >>Thanks, >>-Aditya >> >> >>2015-05-07 Aditya Kumar <hiraditya@msn.com> >> >> * tree-ssa-loop-niter.c (number_of_iterations_exit): Move call >>to dominated_by_p later in the function. >> >>diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c >>index 042f8df..3d49bb8 100644 >>--- a/gcc/tree-ssa-loop-niter.c >>+++ b/gcc/tree-ssa-loop-niter.c >>@@ -1959,11 +1959,6 @@ number_of_iterations_exit (struct loop *loop, >>edge exit, >> affine_iv iv0, iv1; >> bool safe; >> >>- safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); >>- >>- if (every_iteration && !safe) >>- return false; >>- >> niter->assumptions = boolean_false_node; >> last = last_stmt (exit->src); >> if (!last) >>@@ -1972,6 +1967,11 @@ number_of_iterations_exit (struct loop *loop, >>edge exit, >> if (!stmt) >> return false; >> >>+ safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); >>+ >>+ if (every_iteration && !safe) >>+ return false; >>+ >> /* We want the condition for staying inside loop. */ >> code = gimple_cond_code (stmt); >> if (exit->flags & EDGE_TRUE_VALUE) >> >> > >
diff --git a/gcc/tree-ssa-loop-niter.c b/gcc/tree-ssa-loop-niter.c index 042f8df..3d49bb8 100644 --- a/gcc/tree-ssa-loop-niter.c +++ b/gcc/tree-ssa-loop-niter.c @@ -1959,11 +1959,6 @@ number_of_iterations_exit (struct loop *loop, edge exit, affine_iv iv0, iv1; bool safe; - safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); - - if (every_iteration && !safe) - return false; - niter->assumptions = boolean_false_node; last = last_stmt (exit->src); if (!last) @@ -1972,6 +1967,11 @@ number_of_iterations_exit (struct loop *loop, edge exit, if (!stmt) return false; + safe = dominated_by_p (CDI_DOMINATORS, loop->latch, exit->src); + + if (every_iteration && !safe) + return false; + /* We want the condition for staying inside loop. */ code = gimple_cond_code (stmt); if (exit->flags & EDGE_TRUE_VALUE)