gcc:

2005-05-17  Paolo Bonzini  <bonzini@gnu.org>

	* Makefile.in: Add tree-ssa-math-opts.c.
	* expr.c (expand_expr_real_1) <case RDIV_EXPR>: Never emit as a*(1/b).
	* fold-const.c (distribute_real_division): New.
	(fold_binary) <case PLUS_EXPR, case MINUS_EXPR>: Use it.
	* tree-pass.h (pass_cse_reciprocals): New.
	* tree-optimize.c (init_tree_optimization_passes): Run it.
	* tree-ssa-math-opts.c: New file.
	* doc/passes.texi: Document the new pass.

gcc/testsuite:
2005-05-17  Paolo Bonzini  <bonzini@gnu.org>

	* gcc.dg/fold-div-1.c, gcc.dg/recip-1.c, gcc.dg/recip-2.c: New.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@99826 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 7 insertions, 1 deletions

diff --git a/gcc/doc/passes.texi b/gcc/doc/passes.texi
index 8e123667ec5..ad6110e7312 100644
--- a/gcc/doc/passes.texi
+++ b/gcc/doc/passes.texi
@@ -354,7 +354,7 @@ This pass transforms tail recursion into a loop.  It is located in
 
 This pass sinks stores and assignments down the flowgraph closer to it's
 use point.  The pass is located in @file{tree-ssa-sink.c} and is
-described by @code{pass_sink_code}
+described by @code{pass_sink_code}.
 
 @item Partial redundancy elimination
 
@@ -362,6 +362,12 @@ This pass eliminates partially redundant computations, as well as
 performing load motion.  The pass is located in @file{tree-ssa-pre.c}
 and is described by @code{pass_pre}.
 
+Just before partial redundancy elimination, if
+@option{-funsafe-math-optimizations} is on, GCC tries to convert
+divisions to multiplications by the reciprocal.  The pass is located
+in @file{tree-ssa-math-opts.c} and is described by
+@code{pass_cse_reciprocal}.
+
 @item Loop optimization
 
 The main driver of the pass is placed in @file{tree-ssa-loop.c}