8354471: Assertion failure with -XX:-EnableX86ECoreOpts

Reviewed-by: sviswanathan, jbhateja

Author: Volodymyr Paprotski

src/hotspot/cpu/x86/stubGenerator_x86_64_poly_mont.cpp

@@ -564,7 +564,16 @@ address StubGenerator::generate_intpoly_montgomeryMult_P256() {
   address start = __ pc();
   __ enter();
 
-  if (EnableX86ECoreOpts && UseAVX > 1) {
+  if (VM_Version::supports_avx512ifma() && VM_Version::supports_avx512vlbw()) {
+    // Register Map
+    const Register aLimbs  = c_rarg0; // rdi | rcx
+    const Register bLimbs  = c_rarg1; // rsi | rdx
+    const Register rLimbs  = c_rarg2; // rdx | r8
+    const Register tmp     = r9;
+
+    montgomeryMultiply(aLimbs, bLimbs, rLimbs, tmp, _masm);
+  } else {
+    assert(VM_Version::supports_avxifma(), "Require AVX_IFMA support");
     __ push(r12);
     __ push(r13);
     __ push(r14);
@@ -607,14 +616,6 @@ address StubGenerator::generate_intpoly_montgomeryMult_P256() {
     __ pop(r14);
     __ pop(r13);
     __ pop(r12);
-  } else {
-    // Register Map
-    const Register aLimbs  = c_rarg0; // rdi | rcx
-    const Register bLimbs  = c_rarg1; // rsi | rdx
-    const Register rLimbs  = c_rarg2; // rdx | r8
-    const Register tmp     = r9;
-
-    montgomeryMultiply(aLimbs, bLimbs, rLimbs, tmp, _masm);
   }
 
   __ leave();