8310886: C2 SuperWord: Two nodes should be isomorphic if they are loop invariant but pinned at different nodes outside the loop

src/hotspot/share/opto/superword.cpp

@@ -1261,50 +1261,24 @@ bool SuperWord::are_adjacent_refs(Node* s1, Node* s2) {
 //------------------------------isomorphic---------------------------
 // Are s1 and s2 similar?
 bool SuperWord::isomorphic(Node* s1, Node* s2) {
-  if (s1->Opcode() != s2->Opcode()) return false;
-  if (s1->req() != s2->req()) return false;
-  if (!same_velt_type(s1, s2)) return false;
-  if (s1->is_Bool() && s1->as_Bool()->_test._test != s2->as_Bool()->_test._test) return false;
+  if (s1->Opcode() != s2->Opcode() ||
+      s1->req() != s2->req() ||
+      !same_velt_type(s1, s2) ||
+      (s1->is_Bool() && s1->as_Bool()->_test._test != s2->as_Bool()->_test._test)) {
+    return false;
+  }
+
   Node* s1_ctrl = s1->in(0);
   Node* s2_ctrl = s2->in(0);
   // If the control nodes are equivalent, no further checks are required to test for isomorphism.
   if (s1_ctrl == s2_ctrl) {
     return true;
   } else {
-    bool s1_ctrl_inv = ((s1_ctrl == nullptr) ? true : lpt()->is_invariant(s1_ctrl));
-    bool s2_ctrl_inv = ((s2_ctrl == nullptr) ? true : lpt()->is_invariant(s2_ctrl));
     // If the control nodes are not invariant for the loop, fail isomorphism test.
-    if (!s1_ctrl_inv || !s2_ctrl_inv) {
-      return false;
-    }
-    if(s1_ctrl != nullptr && s2_ctrl != nullptr) {
-      if (s1_ctrl->is_Proj()) {
-        s1_ctrl = s1_ctrl->in(0);
-        assert(lpt()->is_invariant(s1_ctrl), "must be invariant");
-      }
-      if (s2_ctrl->is_Proj()) {
-        s2_ctrl = s2_ctrl->in(0);
-        assert(lpt()->is_invariant(s2_ctrl), "must be invariant");
-      }
-      if (!s1_ctrl->is_RangeCheck() || !s2_ctrl->is_RangeCheck()) {
-        return false;
-      }
-    }
-    // Control nodes are invariant. However, we have no way of checking whether they resolve
-    // in an equivalent manner. But, we know that invariant range checks are guaranteed to
-    // throw before the loop (if they would have thrown). Thus, the loop would not have been reached.
-    // Therefore, if the control nodes for both are range checks, we accept them to be isomorphic.
-    for (DUIterator_Fast imax, i = s1->fast_outs(imax); i < imax; i++) {
-      Node* t1 = s1->fast_out(i);
-      for (DUIterator_Fast jmax, j = s2->fast_outs(jmax); j < jmax; j++) {
-        Node* t2 = s2->fast_out(j);
-        if (VectorNode::is_muladds2i(t1) && VectorNode::is_muladds2i(t2)) {
-          return true;
-        }
-      }
-    }
+    const bool s1_ctrl_inv = (s1_ctrl == nullptr) || lpt()->is_invariant(s1_ctrl);
+    const bool s2_ctrl_inv = (s2_ctrl == nullptr) || lpt()->is_invariant(s2_ctrl);
+    return s1_ctrl_inv && s2_ctrl_inv;
   }
-  return false;
 }
 
 //------------------------------independent---------------------------

test/hotspot/jtreg/compiler/lib/ir_framework/IRNode.java

@@ -927,6 +927,22 @@ public class IRNode {
         beforeMatchingNameRegex(MUL, "Mul(I|L|F|D)");
     }
 
+    public static final String MUL_ADD_S2I = PREFIX + "MUL_ADD_S2I" + POSTFIX;
+    static {
+        beforeMatchingNameRegex(MUL_ADD_S2I, "MulAddS2I");
+    }
+
+    public static final String MUL_ADD_VS2VI = VECTOR_PREFIX + "MUL_ADD_VS2VI" + POSTFIX;
+    static {
+        vectorNode(MUL_ADD_VS2VI, "MulAddVS2VI", TYPE_INT);
+    }
+
+    // Can only be used if avx512_vnni is available.
+    public static final String MUL_ADD_VS2VI_VNNI = PREFIX + "MUL_ADD_VS2VI_VNNI" + POSTFIX;
+    static {
+        machOnly(MUL_ADD_VS2VI_VNNI, "vmuladdaddS2I_reg");
+    }
+
     public static final String MUL_D = PREFIX + "MUL_D" + POSTFIX;
     static {
         beforeMatchingNameRegex(MUL_D, "MulD");

test/hotspot/jtreg/compiler/lib/ir_framework/test/IREncodingPrinter.java

@@ -98,6 +98,7 @@ public class IREncodingPrinter {
         "avx512dq",
         "avx512vl",
         "avx512f",
+        "avx512_vnni",
         // AArch64
         "sha3",
         "asimd",

test/hotspot/jtreg/compiler/loopopts/superword/TestMulAddS2I.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8310886
+ * @requires os.arch == "x86_64" | os.arch == "aarch64"
+ * @summary Test MulAddS2I vectorization.
+ * @library /test/lib /
+ * @run driver compiler.loopopts.superword.TestMulAddS2I
+ */
+
+package compiler.loopopts.superword;
+
+import compiler.lib.ir_framework.*;
+import jdk.test.lib.Asserts;
+import jdk.test.lib.Platform;
+
+public class TestMulAddS2I {
+    static final int RANGE = 1024;
+    static final int ITER  = RANGE/2 - 1;
+
+    static short[] sArr1 = new short[RANGE];
+    static short[] sArr2 = new short[RANGE];
+    static final int[] GOLDEN;
+
+    static {
+        for (int i = 0; i < RANGE; i++) {
+            sArr1[i] = (short)(AbstractInfo.getRandom().nextInt());
+            sArr2[i] = (short)(AbstractInfo.getRandom().nextInt());
+        }
+        GOLDEN = test();
+    }
+
+
+    public static void main(String[] args) {
+        if (Platform.isX64() || Platform.isX86()) {
+            TestFramework.runWithFlags("-XX:+UseUnalignedLoadStores");
+            TestFramework.runWithFlags("-XX:-UseUnalignedLoadStores");
+        } else {
+            TestFramework.run();
+        }
+    }
+
+    @Run(test = "test")
+    @Warmup(0)
+    public static void run() {
+        compare(test());
+    }
+
+    public static void compare(int[] out) {
+        for (int i = 0; i < ITER; i++) {
+            Asserts.assertEQ(out[i], GOLDEN[i], "wrong result for out[" + i + "]");
+        }
+    }
+
+    @Test
+    @IR(applyIfCPUFeature = {"sse2", "true"}, applyIf = {"UseUnalignedLoadStores", "true"},
+        counts = {IRNode.MUL_ADD_S2I, "> 0", IRNode.MUL_ADD_VS2VI, "> 0"})
+    @IR(applyIfCPUFeature = {"sse2", "true"}, applyIf = {"UseUnalignedLoadStores", "false"},
+        failOn = {IRNode.MUL_ADD_VS2VI}, // Can only pack LoadS if UseUnalignedLoadStores is true (default if sse4.2)
+        counts = {IRNode.MUL_ADD_S2I, "> 0"})
+    @IR(applyIfCPUFeature = {"asimd", "true"}, applyIf = {"MaxVectorSize", "16"}, // AD file requires vector_length = 16
+            counts = {IRNode.MUL_ADD_S2I, "> 0", IRNode.MUL_ADD_VS2VI, "> 0"})
+    @IR(applyIfCPUFeature = {"avx512_vnni", "true"}, applyIf = {"UseUnalignedLoadStores", "true"},
+            counts = {IRNode.MUL_ADD_S2I, "> 0", IRNode.MUL_ADD_VS2VI_VNNI, "> 0"})
+    public static int[] test() {
+        int[] out = new int[ITER];
+        int[] out2 = new int[ITER];
+        for (int i = 0; i < ITER; i++) {
+            out[i] += ((sArr1[2*i] * sArr1[2*i]) + (sArr1[2*i+1] * sArr1[2*i+1]));
+            out2[i] += out[i];
+        }
+        return out;
+    }
+}