diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-19.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-19.c new file mode 100644 index 00000000000..e98d13fe85b --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-sink-19.c @@ -0,0 +1,21 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-sink1-details -fdump-tree-cddce2-details" } */ + +static int b=4; +int c; + +int +main() +{ + int e[5] = {1,1,1,1,1}; + for (; b >= 0; b--) { + c = e[b]; + } + return 0; +} + +/* We should sink e[b] out of the loop which is possible after + applying store motion to c and b. */ +/* { dg-final { scan-tree-dump "Sinking # VUSE" "sink1" } } */ +/* And remove the loop after final value replacement. */ +/* { dg-final { scan-tree-dump "fix_loop_structure: removing loop" "cddce2" } } */ diff --git a/gcc/tree-ssa-sink.cc b/gcc/tree-ssa-sink.cc index 1c226406feb..8ce4403ddc8 100644 --- a/gcc/tree-ssa-sink.cc +++ b/gcc/tree-ssa-sink.cc @@ -390,6 +390,9 @@ statement_sink_location (gimple *stmt, basic_block frombb, with the use. */ if (gimple_code (use_stmt) == GIMPLE_PHI) { + /* If the PHI defines the virtual operand, ignore it. */ + if (gimple_phi_result (use_stmt) == gimple_vuse (stmt)) + continue; /* In case the PHI node post-dominates the current insert location we can disregard it. But make sure it is not dominating it as well as can happen in a CFG cycle. */