8010941: MinJumpTableSize is set to 18, investigate if that's still optimal

Summary: Lowered the MinJumpTableSize for each platform
Reviewed-by: kvn

src/cpu/sparc/vm/c2_globals_sparc.hpp

@@ -57,6 +57,7 @@ define_pd_global(intx, RegisterCostAreaRatio,        12000);
 define_pd_global(bool, UseTLAB,                      true);
 define_pd_global(bool, ResizeTLAB,                   true);
 define_pd_global(intx, LoopUnrollLimit,              60); // Design center runs on 1.3.1
+define_pd_global(intx, MinJumpTableSize,             5);
 
 // Peephole and CISC spilling both break the graph, and so makes the
 // scheduler sick.

src/cpu/x86/vm/c2_globals_x86.hpp

@@ -30,7 +30,6 @@
 
 // Sets the default values for platform dependent flags used by the server compiler.
 // (see c2_globals.hpp).  Alpha-sorted.
-
 define_pd_global(bool, BackgroundCompilation,        true);
 define_pd_global(bool, UseTLAB,                      true);
 define_pd_global(bool, ResizeTLAB,                   true);
@@ -52,6 +51,7 @@ define_pd_global(intx, OnStackReplacePercentage,     140);
 define_pd_global(intx, ConditionalMoveLimit,         3);
 define_pd_global(intx, FLOATPRESSURE,                6);
 define_pd_global(intx, FreqInlineSize,               325);
+define_pd_global(intx, MinJumpTableSize,             10);
 #ifdef AMD64
 define_pd_global(intx, INTPRESSURE,                  13);
 define_pd_global(intx, InteriorEntryAlignment,       16);

src/share/vm/opto/c2_globals.hpp

@@ -421,7 +421,7 @@
   product(bool, UseDivMod, true,                                            \
           "Use combined DivMod instruction if available")                   \
                                                                             \
-  product(intx, MinJumpTableSize, 18,                                       \
+  product_pd(intx, MinJumpTableSize,                                        \
           "Minimum number of targets in a generated jump table")            \
                                                                             \
   product(intx, MaxJumpTableSize, 65000,                                    \