From: Richard Biener Date: Wed, 31 Oct 2018 11:57:33 +0000 (+0000) Subject: re PR middle-end/70359 (Code size increase for x86/ARM/others compared to gcc-5.3.0) X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ef976be1a23a5171082cf1a569d00573013a175c;p=gcc.git re PR middle-end/70359 (Code size increase for x86/ARM/others compared to gcc-5.3.0) 2018-10-31 Richard Biener 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 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 289bb5a9222..1f45354555a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2018-10-31 Richard Biener + + 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. + 2018-10-31 Claudiu Zissulescu * config/arc/arc-arch.h (ARC_TUNE_ARC7XX): New tune value. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index f2a4a8dad11..84923163780 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,10 @@ +2018-10-31 Richard Biener + + PR middle-end/70359 + PR middle-end/86270 + * gcc.target/i386/pr70359.c: New testcase. + * gcc.target/i386/pr86270.c: Likewise. + 2018-10-31 Claudiu Zissulescu * gcc.target/arc/jumptable.c: New test. diff --git a/gcc/testsuite/gcc.target/i386/pr70359.c b/gcc/testsuite/gcc.target/i386/pr70359.c new file mode 100644 index 00000000000..85b7017e386 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr70359.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +char* inttostr(int i, char* buf, int len) +{ + unsigned int ui = (i > 0) ? i : -i; + char *p = buf + len - 1; + *p = '\0'; + do { + *--p = '0' + (ui % 10); + } while ((ui /= 10) != 0); + if (i < 0) { + *--p = '-'; + } + return p; +} + +/* In out-of-SSA we should have avoided splitting the latch edge of the + loop by inserting copies. */ +/* { dg-final { scan-assembler-times "L\[0-9\]+:" 2 } } */ diff --git a/gcc/testsuite/gcc.target/i386/pr86270.c b/gcc/testsuite/gcc.target/i386/pr86270.c new file mode 100644 index 00000000000..81841ef5bd7 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/pr86270.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +int *a; +long len; + +int +test () +{ + for (int i = 0; i < len + 1; i++) + a[i]=i; +} + +/* Check we do not split the backedge but keep nice loop form. */ +/* { dg-final { scan-assembler-times "L\[0-9\]+:" 2 } } */ diff --git a/gcc/tree-outof-ssa.c b/gcc/tree-outof-ssa.c index fca15e5f898..60f3c40ba7d 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); + } } }