[TurboFan] Remove absolute limit from inlining heuristics.

We have an absolute limit beyond which we don't inline small funcions as
well. The idea behind inlining small functions is that it is cheaper to
inline small functions rather than incurring the overhead due to the call.
Hence it is better not to have a hard limit on inlining small functions.
We have a limit on the number of levels of nesting to avoid really large
graphs in some corner cases.

Bug: v8:6682
Change-Id: If74f666996fe4a42bf266a4e87caabfd7c614b12
Reviewed-on: https://chromium-review.googlesource.com/648975
Commit-Queue: Mythri Alle <mythria@chromium.org>
Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48007}

src/compiler/js-inlining-heuristic.cc

@@ -193,8 +193,7 @@ Reduction JSInliningHeuristic::Reduce(Node* node) {
 
   // Forcibly inline small functions here. In the case of polymorphic inlining
   // small_inline is set only when all functions are small.
-  if (small_inline &&
-      cumulative_count_ <= FLAG_max_inlined_bytecode_size_absolute) {
+  if (small_inline) {
     TRACE("Inlining small function(s) at call site #%d:%s\n", node->id(),
           node->op()->mnemonic());
     return InlineCandidate(candidate, true);

src/flag-definitions.h

@@ -406,9 +406,6 @@ DEFINE_BOOL(turbo_inlining, true, "enable inlining in TurboFan")
 DEFINE_INT(max_inlining_levels, 5, "maximum number of inlining levels")
 DEFINE_INT(max_inlined_bytecode_size, 500,
            "maximum size of bytecode for a single inlining")
-DEFINE_INT(max_inlined_bytecode_size_absolute, 4000,
-           "maximum absolute size of bytecode considered for inlining "
-           "(incl. small functions)")
 DEFINE_INT(max_inlined_bytecode_size_cumulative, 1000,
            "maximum cumulative size of bytecode considered for inlining")
 DEFINE_FLOAT(reserve_inline_budget_scale_factor, 1.2,
@@ -421,8 +418,6 @@ DEFINE_BOOL(stress_inline, false,
             "set high thresholds for inlining to inline as much as possible")
 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlining_levels, 999999)
 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size, 999999)
-DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_absolute,
-                         999999)
 DEFINE_VALUE_IMPLICATION(stress_inline, max_inlined_bytecode_size_cumulative,
                          999999)
 DEFINE_VALUE_IMPLICATION(stress_inline, min_inlining_frequency, 0)