diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/ssa-hoist-7.c | 54 | ||||
| -rw-r--r-- | gcc/tree-ssa-pre.c | 13 |
2 files changed, 63 insertions, 4 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-hoist-7.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-hoist-7.c new file mode 100644 index 0000000..ce9cec6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-hoist-7.c @@ -0,0 +1,54 @@ +/* { dg-options "-O2 -fdump-tree-pre-stats" } */ + +void baz(); +int tem; +void foo (int a, int b, int c, int d, int e, int x, int y, int z) +{ + if (a) + { + if (b) + { + if (c) + { + if (d) + { + if (e) + { + tem = x + y; + } + else + { + if (z) baz (); + tem = x + y; + } + } + else + { + if (z) baz (); + tem = x + y; + } + } + else + { + if (z) baz (); + tem = x + y; + } + } + else + { + if (z) baz (); + tem = x + y; + } + } + else + { + if (z) baz (); + tem = x + y; + } +} + +/* Now inserting x + y five times is unnecessary but the cascading + cannot be avoided with the simple-minded dataflow. But make sure + we do the insertions all in the first iteration. */ +/* { dg-final { scan-tree-dump "insert iterations == 2" "pre" } } */ +/* { dg-final { scan-tree-dump "HOIST inserted: 5" "pre" } } */ diff --git a/gcc/tree-ssa-pre.c b/gcc/tree-ssa-pre.c index bcef972..091ecb3 100644 --- a/gcc/tree-ssa-pre.c +++ b/gcc/tree-ssa-pre.c @@ -3646,6 +3646,15 @@ insert (void) fprintf (dump_file, "Starting insert iteration %d\n", num_iterations); changed = false; + /* Insert expressions for hoisting. Do a backward walk here since + inserting into BLOCK exposes new opportunities in its predecessors. */ + if (flag_code_hoisting) + for (int idx = rpo_num - 1; idx >= 0; --idx) + { + basic_block block = BASIC_BLOCK_FOR_FN (cfun, rpo[idx]); + if (EDGE_COUNT (block->succs) >= 2) + changed |= do_hoist_insertion (block); + } for (int idx = 0; idx < rpo_num; ++idx) { basic_block block = BASIC_BLOCK_FOR_FN (cfun, rpo[idx]); @@ -3680,10 +3689,6 @@ insert (void) if (do_partial_partial) changed |= do_pre_partial_partial_insertion (block, dom); } - - /* Insert expressions for hoisting. */ - if (flag_code_hoisting && EDGE_COUNT (block->succs) >= 2) - changed |= do_hoist_insertion (block); } } |