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

cnqpzhang · Paul Hohensee · commit 23389d08a2b5 · 2025-03-07T17:30:59.000Z
Backport-of: f529bf712d8946584999dfc98abea60c22c97167
diff --git a/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp b/src/hotspot/cpu/aarch64/vm_version_aarch64.cpp
@@ -162,6 +162,9 @@ void VM_Version::initialize() {
         (_model == CPU_MODEL_AMPERE_1A || _model == CPU_MODEL_AMPERE_1B)) {
       FLAG_SET_DEFAULT(CodeEntryAlignment, 32);
     }
+    if (FLAG_IS_DEFAULT(UseSignumIntrinsic)) {
+      FLAG_SET_DEFAULT(UseSignumIntrinsic, true);
+    }
   }
 
   // ThunderX

Original file line number	Diff line number	Diff line change
`@@ -162,6 +162,9 @@ void VM_Version::initialize() {`
`162`	`162`	`(_model == CPU_MODEL_AMPERE_1A \|\| _model == CPU_MODEL_AMPERE_1B)) {`
`163`	`163`	`FLAG_SET_DEFAULT(CodeEntryAlignment, 32);`
`164`	`164`	`}`
	`165`	`+ if (FLAG_IS_DEFAULT(UseSignumIntrinsic)) {`
	`166`	`+ FLAG_SET_DEFAULT(UseSignumIntrinsic, true);`
	`167`	`+ }`
`165`	`168`	`}`
`166`	`169`
`167`	`170`	`// ThunderX`