8350483: AArch64: turn on signum intrinsics by default on Ampere CPUs

cnqpzhang · Andrew Haley · commit 3c0c998e7321 · 2025-04-08T16:55:04.000Z
Backport-of: 23389d08a2b5c0840d2b18fb2e74d2d112b3192d
diff --git a/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp b/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
@@ -158,6 +158,9 @@ void VM_Version::initialize() {
     if (FLAG_IS_DEFAULT(OnSpinWaitInstCount)) {
       FLAG_SET_DEFAULT(OnSpinWaitInstCount, 2);
     }
+    if (FLAG_IS_DEFAULT(UseSignumIntrinsic)) {
+      FLAG_SET_DEFAULT(UseSignumIntrinsic, true);
+    }
   }
 
   // ThunderX

Original file line number	Diff line number	Diff line change
`@@ -158,6 +158,9 @@ void VM_Version::initialize() {`
`158`	`158`	`if (FLAG_IS_DEFAULT(OnSpinWaitInstCount)) {`
`159`	`159`	`FLAG_SET_DEFAULT(OnSpinWaitInstCount, 2);`
`160`	`160`	`}`
	`161`	`+ if (FLAG_IS_DEFAULT(UseSignumIntrinsic)) {`
	`162`	`+ FLAG_SET_DEFAULT(UseSignumIntrinsic, true);`
	`163`	`+ }`
`161`	`164`	`}`
`162`	`165`
`163`	`166`	`// ThunderX`