| Summary: | inline asm impossible constraint in `asm' | ||
|---|---|---|---|
| Product: | gcc | Reporter: | giffordj |
| Component: | rtl-optimization | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED INVALID | ||
| Severity: | normal | CC: | gcc-bugs |
| Priority: | P2 | ||
| Version: | 3.3.1 | ||
| Target Milestone: | --- | ||
| Host: | Target: | ||
| Build: | Known to work: | ||
| Known to fail: | Last reconfirmed: | ||
| Attachments: | Preprocessed Source | ||
We need a full test case, read <http://gcc.gnu.org/bugs.html> Created attachment 4938 [details]
Preprocessed Source
Error Messages /usr/src/java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp: In function `jboolean JVM_CX8Field(JNIEnv*, _jobject*, _jfieldID*, long long int, long long int)': /usr/src/java/hotspot/src/os_cpu/linux_i486/vm/atomic_linux_i486.inline.hpp:50: error: impossible constraint in `asm' Marking invalid to mark it as ... unconfirmed. The problem is with the "o" constriant, if I change it to m (which looks better and is right constraint to use in this case because the memory location could be any where). |
Compiles fine with no -O, but gives impossible constraint in `asm' when compiled with -O2 or -O3. Code inline jlong atomic::compare_and_exchange_long(jlong exchange_value, jlong* dest, jlong compare_value) { jlong old_value; __asm__ volatile ( "pushl %%ebx;mov 4+%1,%%ecx;mov %1,%%ebx;lock;cmpxchg8b (%3);popl %%ebx" : "=A" (old_value) : "o" (exchange_value), "A" (compare_value), "r" (dest) : "%ebx", "%ecx", "memory"); return old_value; }