Makefile.in (tree-switch-conversion.o): Add.

2008-07-01  Martin Jambor  <mjambor@suse.cz>
        * Makefile.in (tree-switch-conversion.o): Add.
        (OBJS-common): Add tree-swtch-conversion.o.
        * passes.c (init_optimization_passes): Add pass_convert_switch.
        * tree-pass.h: (pass_convert_switch): Add.
        * tree-switch-conversion.c: New file.
        * gcc.dg/tree-ssa/cswtch.c: New testcase.
        * common.opt (ftree-cswtch): New option.
        * params.h (PARAM_SWITCH_CONVERSION_BRANCH_RATIO): New parameter.
        * params.def (PARAM_SWITCH_CONVERSION_BRANCH_RATIO): New parameter.
        * opts.c (decode_options): Set flag_tree_switch_conversion when
        optimization level is >= 2.
        * doc/invoke.texi (Optimize Options): Added description of
        -ftree-swtch-conversion and switch-conversion-max-branch-ratio.

From-SVN: r137313

gcc/ChangeLog

+2008-07-01  Martin Jambor  <mjambor@suse.cz>
+        * Makefile.in (tree-switch-conversion.o): Add.
+        (OBJS-common): Add tree-swtch-conversion.o.
+        * passes.c (init_optimization_passes): Add pass_convert_switch.
+        * tree-pass.h: (pass_convert_switch): Add.
+        * tree-switch-conversion.c: New file.
+        * gcc.dg/tree-ssa/cswtch.c: New testcase.
+        * common.opt (ftree-cswtch): New option.
+        * params.h (PARAM_SWITCH_CONVERSION_BRANCH_RATIO): New parameter.
+        * params.def (PARAM_SWITCH_CONVERSION_BRANCH_RATIO): New parameter.
+        * opts.c (decode_options): Set flag_tree_switch_conversion when
+        optimization level is >= 2.
+        * doc/invoke.texi (Optimize Options): Added description of
+        -ftree-swtch-conversion and switch-conversion-max-branch-ratio.
+
 2008-06-30  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* config/darwin-driver.c (darwin_default_min_version): Fix

gcc/Makefile.in

@@ -1176,6 +1176,7 @@ OBJS-common = \
 	tree-profile.o \
 	tree-scalar-evolution.o \
 	tree-sra.o \
+	tree-switch-conversion.o \
 	tree-ssa-address.o \
 	tree-ssa-alias.o \
 	tree-ssa-alias-warnings.o \
@@ -2629,6 +2630,11 @@ tree-sra.o : tree-sra.c $(CONFIG_H) $(SYSTEM_H) $(TREE_H) $(RTL_H) \
     $(TIMEVAR_H) $(TM_H) coretypes.h $(TREE_DUMP_H) $(TREE_GIMPLE_H) \
     langhooks.h tree-pass.h $(FLAGS_H) $(EXPR_H) $(BASIC_BLOCK_H) \
     bitmap.h $(GGC_H) hard-reg-set.h $(OBSTACK_H) $(PARAMS_H) $(TARGET_H)
+tree-switch-conversion.o : tree-switch-conversion.c $(CONFIG_H) $(SYSTEM_H) \
+    $(TREE_H) $(TM_P_H) $(TREE_FLOW_H) $(DIAGNOSTIC_H) $(TREE_INLINE_H) \
+    $(TIMEVAR_H) $(TM_H) coretypes.h $(TREE_DUMP_H) $(TREE_GIMPLE_H) \
+    tree-pass.h $(FLAGS_H) $(EXPR_H) $(BASIC_BLOCK_H) output.h \
+    $(GGC_H) $(OBSTACK_H) $(PARAMS_H) $(CPPLIB_H) $(PARAMS_H)
 tree-complex.o : tree-complex.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TREE_H) \
     $(TM_H) $(RTL_H) $(REAL_H) $(FLAGS_H) $(TREE_FLOW_H) $(TREE_GIMPLE_H) \
     tree-iterator.h tree-pass.h tree-ssa-propagate.h $(DIAGNOSTIC_H)

gcc/common.opt

@@ -1088,6 +1088,10 @@ ftree-cselim
 Common Report Var(flag_tree_cselim) Init(2) Optimization
 Transform condition stores into unconditional ones
 
+ftree-switch-conversion
+Common Report Var(flag_tree_switch_conversion) Optimization
+Perform conversions of switch initializations.
+
 ftree-dce
 Common Report Var(flag_tree_dce) Optimization
 Enable SSA dead code elimination optimization on trees

gcc/doc/invoke.texi

@@ -359,10 +359,10 @@ Objective-C and Objective-C++ Dialects}.
 -ftree-loop-distribution @gol
 -ftree-loop-ivcanon -ftree-loop-linear -ftree-loop-optimize @gol
 -ftree-parallelize-loops=@var{n} -ftree-pre -ftree-reassoc @gol
--ftree-sink -ftree-sra -ftree-store-ccp -ftree-ter @gol
--ftree-vect-loop-version -ftree-vectorize -ftree-vrp -funit-at-a-time @gol
--funroll-all-loops -funroll-loops -funsafe-loop-optimizations @gol
--funsafe-math-optimizations -funswitch-loops @gol
+-ftree-sink -ftree-sra -ftree-store-ccp -ftree-switch-conversion @gol
+-ftree-ter -ftree-vect-loop-version -ftree-vectorize -ftree-vrp @gol
+-funit-at-a-time -funroll-all-loops -funroll-loops @gol
+-funsafe-loop-optimizations -funsafe-math-optimizations -funswitch-loops @gol
 -fvariable-expansion-in-unroller -fvect-cost-model -fvpt -fweb @gol
 -fwhole-program @gol
 --param @var{name}=@var{value}
@@ -5194,6 +5194,7 @@ also turns on the following optimization flags:
 -fsched-interblock  -fsched-spec @gol
 -fschedule-insns  -fschedule-insns2 @gol
 -fstrict-aliasing -fstrict-overflow @gol
+-ftree-switch-conversion @gol
 -ftree-pre @gol
 -ftree-vrp}
 
@@ -5868,6 +5869,11 @@ pass operates on both local scalar variables and memory stores and
 loads (global variables, structures, arrays, etc).  This flag is
 enabled by default at @option{-O2} and higher.
 
+@item -ftree-switch-conversion
+Perform conversion of simple initializations in a switch to
+initializations from a scalar array.  This flag is enabled by default
+at @option{-O2} and higher.
+
 @item -ftree-dce
 @opindex ftree-dce
 Perform dead code elimination (DCE) on trees.  This flag is enabled by
@@ -7344,6 +7350,11 @@ mechanism for comparing types in C++ and Objective-C++.  However, if
 bugs in the canonical type system are causing compilation failures,
 set this value to 0 to disable canonical types.
 
+@item switch-conversion-max-branch-ratio
+Switch initialization conversion will refuse to create arrays that are
+bigger than @option{cswtch-max-branch-ratio} times the number of
+branches in the switch.
+
 @item max-partial-antic-length
 Maximum length of the partial antic set computed during the tree
 partial redundancy elimination optimization (@option{-ftree-pre}) when

gcc/opts.c

@@ -891,6 +891,7 @@ decode_options (unsigned int argc, const char **argv)
       flag_reorder_functions = 1;
       flag_tree_store_ccp = 1;
       flag_tree_vrp = 1;
+      flag_tree_switch_conversion = 1;
 
       if (!optimize_size)
 	{

gcc/params.def

@@ -710,6 +710,15 @@ DEFPARAM (PARAM_DF_DOUBLE_QUEUE_THRESHOLD_FACTOR,
 	  "Multiplier used for determining the double-queueing threshold",
 	  2, 0, 0)
 
+/* Switch initialization conversion will refuse to create arrays that are
+   bigger than this parameter times the number of switch branches.  */
+
+DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
+	  "switch-conversion-max-branch-ratio",
+	  "The maximum ratio between array size and switch branches for "
+	  "a switch conversion to take place",
+	  8, 1, 0)
+
 /*
 Local variables:
 mode:c

gcc/params.h

@@ -167,4 +167,6 @@ typedef enum compiler_param
   PARAM_VALUE (PARAM_L2_CACHE_SIZE)
 #define USE_CANONICAL_TYPES \
   PARAM_VALUE (PARAM_USE_CANONICAL_TYPES)
+#define SWITCH_CONVERSION_BRANCH_RATIO \
+  PARAM_VALUE (PARAM_SWITCH_CONVERSION_BRANCH_RATIO)
 #endif /* ! GCC_PARAMS_H */

gcc/passes.c

@@ -572,6 +572,7 @@ init_optimization_passes (void)
 	  NEXT_PASS (pass_update_address_taken);
 	  NEXT_PASS (pass_simple_dse);
 	  NEXT_PASS (pass_tail_recursion);
+	  NEXT_PASS (pass_convert_switch);
           NEXT_PASS (pass_profile);
 	  NEXT_PASS (pass_release_ssa_names);
 	}

gcc/testsuite/gcc.dg/tree-ssa/cswtch.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-switchconv" } */
+/* { dg-do run } */
+
+extern void abort (void);
+
+static int X, Y;
+
+int check(int param)
+{
+  int a = 0;
+  int b = 1;
+  
+  switch (param) 
+    {
+    case -2:
+      a = 0;
+      b = -1;
+      break;
+    case 1:
+    case 2:
+      a = 8;
+      b = 6;
+      break;
+    case 3:
+      a = 9;
+      b = 5;
+      break;
+    case 6:
+      a = 10;
+      b = 4;
+      break;
+    default:
+      a = 16;
+      b = 1;
+    }
+  
+  X = a;
+  Y = b;
+  return 0;
+}
+
+void assertions(int a, int b)
+{
+  if (X != a || Y != b)
+    abort();  
+
+  return;
+}
+
+int main ()
+{
+  check (-10);
+  assertions (16, 1);
+
+  check (-2);
+  assertions (0, -1);
+
+  check(1);
+  assertions (8, 6);
+
+  check(2);
+  assertions (8, 6);
+
+  check(3);
+  assertions (9, 5);
+
+  check(5);
+  assertions (16, 1);
+
+  check(6);
+  assertions (10, 4);
+
+  check(12);
+  assertions (16, 1);
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump "Switch converted" "switchconv" } } */
+/* { dg-final { cleanup-tree-dump "switchconv" } } */

gcc/tree-pass.h

@@ -508,6 +508,7 @@ extern struct gimple_opt_pass pass_O0_always_inline;
 extern struct gimple_opt_pass pass_inline_parameters;
 extern struct gimple_opt_pass pass_all_early_optimizations;
 extern struct gimple_opt_pass pass_update_address_taken;
+extern struct gimple_opt_pass pass_convert_switch;
 
 /* The root of the compilation pass tree, once constructed.  */
 extern struct opt_pass *all_passes, *all_ipa_passes, *all_lowering_passes;