diff --git a/.hgtags b/.hgtags
index a4580d1..a09db32 100644
--- a/.hgtags
+++ b/.hgtags
@@ -578,3 +578,6 @@
 e64b1cb48d6e7703928a9d1da106fc27f8cb65fd jdk-9+173
 944791f8160185bffa13fbb821fc09b6198f1f25 jdk-9+174
 8f04d457168b9f1f4a1b2c37f49e0513ca9d33a7 jdk-9+175
+2ab74e5dbdc2b6a962c865500cafd23cf387dc60 jdk-9+176
+1ca8f038fceb88c640badf9bd18905205bc63b43 jdk-9+177
+9d032191f82fca5ba0aac98682f69c4ff0f1283d jdk-9+178
diff --git a/src/cpu/aarch64/vm/c2_globals_aarch64.hpp b/src/cpu/aarch64/vm/c2_globals_aarch64.hpp
index 9a16dd7..69c8cc0 100644
--- a/src/cpu/aarch64/vm/c2_globals_aarch64.hpp
+++ b/src/cpu/aarch64/vm/c2_globals_aarch64.hpp
@@ -50,12 +50,11 @@
 define_pd_global(intx, FLOATPRESSURE,                64);
 define_pd_global(intx, FreqInlineSize,               325);
 define_pd_global(intx, MinJumpTableSize,             10);
-define_pd_global(intx, INTPRESSURE,                  25);
+define_pd_global(intx, INTPRESSURE,                  24);
 define_pd_global(intx, InteriorEntryAlignment,       16);
 define_pd_global(intx, NewSizeThreadIncrease, ScaleForWordSize(4*K));
 define_pd_global(intx, LoopUnrollLimit,              60);
 define_pd_global(intx, LoopPercentProfileLimit,      10);
-define_pd_global(intx, PostLoopMultiversioning,      false);
 // InitialCodeCacheSize derived from specjbb2000 run.
 define_pd_global(intx, InitialCodeCacheSize,         2496*K); // Integral multiple of CodeCacheExpansionSize
 define_pd_global(intx, CodeCacheExpansionSize,       64*K);
diff --git a/src/cpu/arm/vm/c2_globals_arm.hpp b/src/cpu/arm/vm/c2_globals_arm.hpp
index 4b424ed..2c09196 100644
--- a/src/cpu/arm/vm/c2_globals_arm.hpp
+++ b/src/cpu/arm/vm/c2_globals_arm.hpp
@@ -70,7 +70,6 @@
 define_pd_global(bool, ResizeTLAB,                   true);
 define_pd_global(intx, LoopUnrollLimit,              60); // Design center runs on 1.3.1
 define_pd_global(intx, LoopPercentProfileLimit,      10);
-define_pd_global(intx, PostLoopMultiversioning,      false);
 define_pd_global(intx, MinJumpTableSize,             16);
 
 // Peephole and CISC spilling both break the graph, and so makes the
diff --git a/src/cpu/ppc/vm/c2_globals_ppc.hpp b/src/cpu/ppc/vm/c2_globals_ppc.hpp
index e755e98..fd61e5d 100644
--- a/src/cpu/ppc/vm/c2_globals_ppc.hpp
+++ b/src/cpu/ppc/vm/c2_globals_ppc.hpp
@@ -55,7 +55,6 @@
 define_pd_global(bool, ResizeTLAB,                   true);
 define_pd_global(intx, LoopUnrollLimit,              60);
 define_pd_global(intx, LoopPercentProfileLimit,      10);
-define_pd_global(intx, PostLoopMultiversioning,      false);
 
 // Peephole and CISC spilling both break the graph, and so make the
 // scheduler sick.
diff --git a/src/cpu/s390/vm/c2_globals_s390.hpp b/src/cpu/s390/vm/c2_globals_s390.hpp
index 2c00ec8..86a1d10 100644
--- a/src/cpu/s390/vm/c2_globals_s390.hpp
+++ b/src/cpu/s390/vm/c2_globals_s390.hpp
@@ -56,7 +56,6 @@
 define_pd_global(bool, ResizeTLAB,                   true);
 define_pd_global(intx, LoopUnrollLimit,              60);
 define_pd_global(intx, LoopPercentProfileLimit,      10);
-define_pd_global(intx, PostLoopMultiversioning,      false);
 define_pd_global(intx, MinJumpTableSize,             18);
 
 // Peephole and CISC spilling both break the graph, and so makes the
diff --git a/src/cpu/sparc/vm/c2_globals_sparc.hpp b/src/cpu/sparc/vm/c2_globals_sparc.hpp
index 10e6799..7e7cddc 100644
--- a/src/cpu/sparc/vm/c2_globals_sparc.hpp
+++ b/src/cpu/sparc/vm/c2_globals_sparc.hpp
@@ -53,7 +53,6 @@
 define_pd_global(bool, ResizeTLAB,                   true);
 define_pd_global(intx, LoopUnrollLimit,              60); // Design center runs on 1.3.1
 define_pd_global(intx, LoopPercentProfileLimit,      10);
-define_pd_global(intx, PostLoopMultiversioning,      false);
 define_pd_global(intx, MinJumpTableSize,             5);
 
 // Peephole and CISC spilling both break the graph, and so makes the
diff --git a/src/cpu/x86/vm/c2_globals_x86.hpp b/src/cpu/x86/vm/c2_globals_x86.hpp
index c193029..e805cad 100644
--- a/src/cpu/x86/vm/c2_globals_x86.hpp
+++ b/src/cpu/x86/vm/c2_globals_x86.hpp
@@ -47,7 +47,6 @@
 define_pd_global(intx, FreqInlineSize,               325);
 define_pd_global(intx, MinJumpTableSize,             10);
 define_pd_global(intx, LoopPercentProfileLimit,      30);
-define_pd_global(intx, PostLoopMultiversioning,      true);
 #ifdef AMD64
 define_pd_global(intx, INTPRESSURE,                  13);
 define_pd_global(intx, FLOATPRESSURE,                14);
diff --git a/src/cpu/x86/vm/globals_x86.hpp b/src/cpu/x86/vm/globals_x86.hpp
index 5673abb..748a1af 100644
--- a/src/cpu/x86/vm/globals_x86.hpp
+++ b/src/cpu/x86/vm/globals_x86.hpp
@@ -116,7 +116,7 @@
   product(bool, UseStoreImmI16, true,                                       \
           "Use store immediate 16-bits value instruction on x86")           \
                                                                             \
-  product(intx, UseAVX, 99,                                                 \
+  product(intx, UseAVX, 2,                                                  \
           "Highest supported AVX instructions set on x86/x64")              \
           range(0, 99)                                                      \
                                                                             \
diff --git a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/JVMCIVersionCheck.java b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/JVMCIVersionCheck.java
index abae7a3..ba759b7 100644
--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/JVMCIVersionCheck.java
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.hotspot/src/org/graalvm/compiler/hotspot/JVMCIVersionCheck.java
@@ -23,6 +23,7 @@
 package org.graalvm.compiler.hotspot;
 
 import java.util.Formatter;
+import java.util.Objects;
 
 /**
  * Mechanism for checking that the current Java runtime environment supports the minimum JVMCI API
@@ -37,10 +38,11 @@
 class JVMCIVersionCheck {
 
     private static final int JVMCI8_MIN_MAJOR_VERSION = 0;
-    private static final int JVMCI8_MIN_MINOR_VERSION = 23;
+    private static final int JVMCI8_MIN_MINOR_VERSION = 26;
 
-    // Will be updated once an ea build with the required JVMCI API is available.
-    private static final int JVMCI9_MIN_EA_BUILD = 143;
+    // MAX_VALUE indicates that no current EA version is compatible with Graal.
+    // Note: Keep README.md in sync with the EA version support checked here.
+    private static final int JVMCI9_MIN_EA_BUILD = 176;
 
     private static void failVersionCheck(boolean exit, String reason, Object... args) {
         Formatter errorMessage = new Formatter().format(reason, args);
@@ -77,13 +79,27 @@
                 start += "-jvmci-".length();
                 int end = vmVersion.indexOf('.', start);
                 if (end > 0) {
-                    int major = Integer.parseInt(vmVersion.substring(start, end));
+                    int major;
+                    try {
+                        major = Integer.parseInt(vmVersion.substring(start, end));
+                    } catch (NumberFormatException e) {
+                        failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal.%n" +
+                                        "Cannot read JVMCI major version from java.vm.version property: %s.%n", vmVersion);
+                        return;
+                    }
                     start = end + 1;
                     end = start;
                     while (end < vmVersion.length() && Character.isDigit(vmVersion.charAt(end))) {
                         end++;
                     }
-                    int minor = Integer.parseInt(vmVersion.substring(start, end));
+                    int minor;
+                    try {
+                        minor = Integer.parseInt(vmVersion.substring(start, end));
+                    } catch (NumberFormatException e) {
+                        failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal.%n" +
+                                        "Cannot read JVMCI minor version from java.vm.version property: %s.%n", vmVersion);
+                        return;
+                    }
                     if (major >= JVMCI8_MIN_MAJOR_VERSION && minor >= JVMCI8_MIN_MINOR_VERSION) {
                         return;
                     }
@@ -96,7 +112,7 @@
                             "Cannot read JVMCI version from java.vm.version property: %s.%n", vmVersion);
         } else {
             if (vmVersion.contains("SNAPSHOT")) {
-                // The snapshot of http://hg.openjdk.java.net/jdk9/hs tip is expected to work
+                // The snapshot of http://hg.openjdk.java.net/jdk9/dev tip is expected to work
                 return;
             }
             if (vmVersion.contains("internal")) {
@@ -104,23 +120,36 @@
                 return;
             }
             // http://openjdk.java.net/jeps/223
-            // Only support EA builds until GA is available
-            if (vmVersion.startsWith("9-ea+")) {
-                int start = "9-ea+".length();
+            if (vmVersion.startsWith("9+")) {
+                int start = "9+".length();
                 int end = start;
                 end = start;
                 while (end < vmVersion.length() && Character.isDigit(vmVersion.charAt(end))) {
                     end++;
                 }
-                int build = Integer.parseInt(vmVersion.substring(start, end));
+                int build;
+                try {
+                    build = Integer.parseInt(vmVersion.substring(start, end));
+                } catch (NumberFormatException e) {
+                    failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal.%n" +
+                                    "Cannot read JDK9 EA build number from java.vm.version property: %s.%n", vmVersion);
+                    return;
+                }
                 if (build >= JVMCI9_MIN_EA_BUILD) {
                     return;
                 }
-                failVersionCheck(exitOnFailure, "The VM is an insufficiently recent EA JDK9 build for Graal: %d < %d.%n", build, JVMCI9_MIN_EA_BUILD);
+                // Using Object.equals suppresses Eclipse's "Dead code" warning.
+                // Unfortunately @SuppressWarnings("unused") can only be applied at method level.
+                if (Objects.equals(JVMCI9_MIN_EA_BUILD, Integer.MAX_VALUE)) {
+                    failVersionCheck(exitOnFailure, "This version of Graal is not compatible with any JDK 9 Early Access build.%n");
+                } else {
+                    failVersionCheck(exitOnFailure, "The VM is an insufficiently recent EA JDK9 build for Graal: %d < %d.%n", build, JVMCI9_MIN_EA_BUILD);
+                }
                 return;
+            } else {
+                // Graal will be compatible with all JDK versions as of 9 GA
+                // until a JVMCI API change is made in a 9u or later release.
             }
-            failVersionCheck(exitOnFailure, "The VM does not support the minimum JVMCI API version required by Graal.%n" +
-                            "Cannot read JDK9 EA build number from java.vm.version property: %s.%n", vmVersion);
         }
     }
 
diff --git a/src/share/vm/opto/c2_globals.hpp b/src/share/vm/opto/c2_globals.hpp
index 49bcbf4..3ae2e20 100644
--- a/src/share/vm/opto/c2_globals.hpp
+++ b/src/share/vm/opto/c2_globals.hpp
@@ -181,7 +181,7 @@
            "Map number of unrolls for main loop via "                       \
            "Superword Level Parallelism analysis")                          \
                                                                             \
-  diagnostic_pd(bool, PostLoopMultiversioning,                              \
+  experimental(bool, PostLoopMultiversioning, false,                        \
            "Multi versioned post loops to eliminate range checks")          \
                                                                             \
   notproduct(bool, TraceSuperWordLoopUnrollAnalysis, false,                 \
diff --git a/test/compiler/rangechecks/TestRangeCheckEliminationDisabled.java b/test/compiler/rangechecks/TestRangeCheckEliminationDisabled.java
index 2c1b5e9..c55a9ad 100644
--- a/test/compiler/rangechecks/TestRangeCheckEliminationDisabled.java
+++ b/test/compiler/rangechecks/TestRangeCheckEliminationDisabled.java
@@ -26,7 +26,7 @@
  * @bug 8154763
  * @summary Tests PostLoopMultiversioning with RangeCheckElimination disabled.
  * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions
- *                   -XX:+PostLoopMultiversioning -XX:-RangeCheckElimination
+ *                   -XX:+UnlockExperimentalVMOptions -XX:+PostLoopMultiversioning -XX:-RangeCheckElimination
  *                   compiler.rangechecks.TestRangeCheckEliminationDisabled
  */