687e30d9d7
This is a duplication of volatile loads introduced during GCC 9 development by the 2->2 mechanism of the RTL combiner. There is already a substantial checking for volatile references in can_combine_p but it implicitly assumes that the combination reduces the number of instructions, which is of course not the case here. So the fix teaches try_combine to abort the combination when it is about to make a copy of volatile references to preserve them. gcc/ PR rtl-optimization/102306 * combine.c (try_combine): Abort the combination if we are about to duplicate volatile references. gcc/testsuite/ * gcc.target/sparc/20210917-1.c: New test.
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