8358592: Assert in Assembler::ptest due to missing SSE42 support #26151

hgqxjj · 2025-07-07T02:52:10Z

Setting "-XX:UseSSE=1" in command line prevents the code from entering the block shown below, which causes UseSSE42Intrinsics to not be correctly set. Because supports_sse3() return false.

in addition , setting "-XX:+UseSSE42Intrinsics" in command line set UseVectorizedMismatchIntrinsic to True shown below.

The above code causes the ptest instruction to be invoked.
The assertion "assert(VM_Version::supports_sse4_1() || VM_Version::supports_avx(), "")" in ptest was triggered and caused the crash because of the following reason:
Setting "-XX:UseSSE=1" in command line cause "CPU_SSE4_1" was cleared and cause "VM_Version::supports_sse4_1()" return false ,related code as below:

Setting "-XX:UseSSE=1" in command line cause "UseAVX=0" and cause "VM_Version::supports_avx()" return false ,related code as below:

all of these above cause this issue.
i fix this issue by correcting UseSSE42Intrinsics to false when "UseSSE" in command line was set to 1, so that UseVectorizedMismatchIntrinsic will be set false and ptest was not triggered.

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JDK-8358592: Assert in Assembler::ptest due to missing SSE42 support (Bug - P4)

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Setting "-XX:UseSSE=1" in command line prevents the code from entering the block which causes UseSSE42Intrinsics to not be correctly set.

bridgekeeper · 2025-07-07T02:52:44Z

👋 Welcome back hgqxjj! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

openjdk · 2025-07-07T02:53:14Z

❗ This change is not yet ready to be integrated.
See the Progress checklist in the description for automated requirements.

openjdk · 2025-07-07T02:53:48Z

@hgqxjj The following label will be automatically applied to this pull request:

hotspot

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

mlbridge · 2025-07-07T02:57:13Z

Webrevs

run on x86_64

TobiHartmann

The fix looks reasonable to me but I'm not an expert in this code.

TobiHartmann · 2025-07-09T13:12:48Z

test/hotspot/jtreg/compiler/intrinsics/Test8358592.java

+ * @requires vm.debug
+ * @requires os.arch == "x86_64"
+ * @library /test/lib
+ * @run main/othervm Test8358592


I think this test should go to /hotspot/jtreg/compiler/arguments/ and have a more descriptive name (we generally try not use bug numbers for tests anymore).

TobiHartmann · 2025-07-09T13:13:23Z

test/hotspot/jtreg/compiler/intrinsics/Test8358592.java

+
+public class Test8358592 {
+    public static void main(String[] args) throws Exception {
+        ProcessBuilder pb = ProcessTools.createTestJavaProcessBuilder(


Instead of spawning a new process, you can just pass the arguments via @run main/othervm, see for example test/hotspot/jtreg/compiler/arguments/TestC1Globals.java.

TobiHartmann · 2025-07-09T13:19:37Z

src/hotspot/cpu/x86/vm_version_x86.cpp

@@ -1491,6 +1491,8 @@ void VM_Version::get_processor_features() {
        }
        FLAG_SET_DEFAULT(UseSSE42Intrinsics, false);
      }
+    }else{


Suggested change

}else{

} else {

TobiHartmann · 2025-07-09T13:19:44Z

src/hotspot/cpu/x86/vm_version_x86.cpp

@@ -1643,6 +1645,8 @@ void VM_Version::get_processor_features() {
        }
        FLAG_SET_DEFAULT(UseSSE42Intrinsics, false);
      }
+    }else{


Suggested change

}else{

} else {

hgqxjj · 2025-07-10T03:36:43Z

hi @TobiHartmann , Thanks a lot for the detailed review, i already update PR and please taking another look when you have time .
Also, since you mentioned you're not an expert in this area, would it make sense to ping someone more familiar?

8358592: Assert in Assembler::ptest due to missing SSE42 support

90bad7d

Setting "-XX:UseSSE=1" in command line prevents the code from entering the block which causes UseSSE42Intrinsics to not be correctly set.

openjdk bot added the rfr Pull request is ready for review label Jul 7, 2025

openjdk bot added the hotspot hotspot-dev@openjdk.org label Jul 7, 2025

hgqxjj and others added 3 commits July 9, 2025 04:20

Merge remote-tracking branch 'upstream/master' into 8358592

167216e

add regression test for JDK-8358592

0684264

Update Test8358592.java

1fe904d

run on x86_64

TobiHartmann suggested changes Jul 9, 2025

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update regression test

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8358592: Assert in Assembler::ptest due to missing SSE42 support #26151

8358592: Assert in Assembler::ptest due to missing SSE42 support #26151

hgqxjj commented Jul 7, 2025 •

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8358592: Assert in Assembler::ptest due to missing SSE42 support #26151

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8358592: Assert in Assembler::ptest due to missing SSE42 support #26151

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