params.def (PARAM_MAX_COMBINE_INSNS): New.

2014-07-23  Richard Biener  <rguenther@suse.de>

	* params.def (PARAM_MAX_COMBINE_INSNS): New.
	* combine.c: Include statistics.h and params.h.
	(combine_instructions): Guard three and four insn combines
	with max-combine-insns value.  Record statistics for combines
	performed.
	* doc/invoke.texi (max-combine-insns): Document new param.

From-SVN: r212923

gcc/ChangeLog

+2014-07-23  Richard Biener  <rguenther@suse.de>
+
+	* params.def (PARAM_MAX_COMBINE_INSNS): New.
+	* combine.c: Include statistics.h and params.h.
+	(combine_instructions): Guard three and four insn combines
+	with max-combine-insns value.  Record statistics for combines
+	performed.
+	* doc/invoke.texi (max-combine-insns): Document new param.
+
 2014-07-23  Roman Gareev  <gareevroman@gmail.com>
 
 	* graphite-isl-ast-to-gimple.c:

gcc/doc/invoke.texi

@@ -10006,6 +10006,10 @@ The maximum size measured as number of RTLs that can be recorded in an expressio
 in combiner for a pseudo register as last known value of that register.  The default
 is 10000.
 
+@item max-combine-insns
+The maximum number of instructions the RTL combiner tries to combine.
+The default value is 2 at @option{-Og} and 4 otherwise.
+
 @item integer-share-limit
 Small integer constants can use a shared data structure, reducing the
 compiler's memory usage and increasing its speed.  This sets the maximum

gcc/params.def

@@ -673,6 +673,11 @@ DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 	 "The maximum number of RTL nodes that can be recorded as combiner's last value",
 	 10000, 0, 0)
 
+DEFPARAM(PARAM_MAX_COMBINE_INSNS,
+	 "max-combine-insns",
+	 "The maximum number of insns combine tries to combine",
+	 4, 2, 4)
+
 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
    {signed,unsigned} integral types.  This determines N.
    Experimentation shows 251 to be a good value that generates the