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| author | Richard Biener <rguenther@suse.de> | 2018-10-31 11:57:33 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2018-10-31 11:57:33 +0000 |
| commit | ef976be1a23a5171082cf1a569d00573013a175c (patch) | |
| tree | 782afd083e18def3f782fe1b3164a3d22a3288ae /gcc/tree-outof-ssa.c | |
| parent | 635aeaa20ffdf6e794f180cc8e053e8dc46db760 (diff) | |
| download | gcc-ef976be1a23a5171082cf1a569d00573013a175c.zip gcc-ef976be1a23a5171082cf1a569d00573013a175c.tar.gz gcc-ef976be1a23a5171082cf1a569d00573013a175c.tar.bz2 | |
re PR middle-end/70359 (Code size increase for x86/ARM/others compared to gcc-5.3.0)
2018-10-31 Richard Biener <rguenther@suse.de>
PR middle-end/70359
PR middle-end/86270
* tree-outof-ssa.c (insert_backedge_copies): Restrict
copy generation to useful cases. Place the copy before
the definition of the backedge value when possible.
* gcc.target/i386/pr70359.c: New testcase.
* gcc.target/i386/pr86270.c: Likewise.
From-SVN: r265677
Diffstat (limited to 'gcc/tree-outof-ssa.c')
| -rw-r--r-- | gcc/tree-outof-ssa.c | 46 |
1 files changed, 39 insertions, 7 deletions
diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c index fca15e5..60f3c40 100644 --- a/gcc/tree-outof-ssa.c +++ b/gcc/tree-outof-ssa.c @@ -1171,15 +1171,19 @@ insert_backedge_copies (void) { tree arg = gimple_phi_arg_def (phi, i); edge e = gimple_phi_arg_edge (phi, i); + /* We are only interested in copies emitted on critical + backedges. */ + if (!(e->flags & EDGE_DFS_BACK) + || !EDGE_CRITICAL_P (e)) + continue; /* If the argument is not an SSA_NAME, then we will need a - constant initialization. If the argument is an SSA_NAME with - a different underlying variable then a copy statement will be - needed. */ - if ((e->flags & EDGE_DFS_BACK) - && (TREE_CODE (arg) != SSA_NAME - || SSA_NAME_VAR (arg) != SSA_NAME_VAR (result) - || trivially_conflicts_p (bb, result, arg))) + constant initialization. If the argument is an SSA_NAME then + a copy statement may be needed. First handle the case + where we cannot insert before the argument definition. */ + if (TREE_CODE (arg) != SSA_NAME + || (gimple_code (SSA_NAME_DEF_STMT (arg)) == GIMPLE_PHI + && trivially_conflicts_p (bb, result, arg))) { tree name; gassign *stmt; @@ -1226,6 +1230,34 @@ insert_backedge_copies (void) gsi_insert_after (&gsi2, stmt, GSI_NEW_STMT); SET_PHI_ARG_DEF (phi, i, name); } + /* Insert a copy before the definition of the backedge value + and adjust all conflicting uses. */ + else if (trivially_conflicts_p (bb, result, arg)) + { + gimple *def = SSA_NAME_DEF_STMT (arg); + if (gimple_nop_p (def) + || gimple_code (def) == GIMPLE_PHI) + continue; + tree name = copy_ssa_name (result); + gimple *stmt = gimple_build_assign (name, result); + imm_use_iterator imm_iter; + gimple *use_stmt; + /* The following matches trivially_conflicts_p. */ + FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, result) + { + if (gimple_bb (use_stmt) != bb + || (gimple_code (use_stmt) != GIMPLE_PHI + && (maybe_renumber_stmts_bb (bb), true) + && gimple_uid (use_stmt) > gimple_uid (def))) + { + use_operand_p use; + FOR_EACH_IMM_USE_ON_STMT (use, imm_iter) + SET_USE (use, name); + } + } + gimple_stmt_iterator gsi = gsi_for_stmt (def); + gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); + } } } |