From cb0c7e386faba08c9e6a15fbf3815aca04454dbb Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Sat, 16 Aug 2014 17:38:04 +0000 Subject: [PATCH] Fix if-conversion pass for dead type-unsafe code 2014-08-15 Tom de Vries Backport from mainline: 2014-08-14 Tom de Vries PR rtl-optimization/62004 PR rtl-optimization/62030 * ifcvt.c (rtx_interchangeable_p): New function. (noce_try_move, noce_process_if_block): Use rtx_interchangeable_p. * gcc.dg/pr62004.c: New test. * gcc.dg/pr62030.c: Same. * gcc.target/mips/pr62030-octeon.c: Same. 2014-08-05 Richard Biener * emit-rtl.h (mem_attrs_eq_p): Declare. * emit-rtl.c (mem_attrs_eq_p): Export. From-SVN: r214067 --- gcc/ChangeLog | 15 ++++++ gcc/emit-rtl.c | 2 +- gcc/emit-rtl.h | 3 ++ gcc/ifcvt.c | 31 ++++++++++-- gcc/testsuite/ChangeLog | 11 ++++ gcc/testsuite/gcc.dg/pr62004.c | 47 +++++++++++++++++ gcc/testsuite/gcc.dg/pr62030.c | 50 +++++++++++++++++++ .../gcc.target/mips/pr62030-octeon.c | 50 +++++++++++++++++++ 8 files changed, 205 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/pr62004.c create mode 100644 gcc/testsuite/gcc.dg/pr62030.c create mode 100644 gcc/testsuite/gcc.target/mips/pr62030-octeon.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index cadb4efcf8ac..bd2e79b7dcf9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,18 @@ +2014-08-15 Tom de Vries + + Backport from mainline: + 2014-08-14 Tom de Vries + + PR rtl-optimization/62004 + PR rtl-optimization/62030 + * ifcvt.c (rtx_interchangeable_p): New function. + (noce_try_move, noce_process_if_block): Use rtx_interchangeable_p. + + 2014-08-05 Richard Biener + + * emit-rtl.h (mem_attrs_eq_p): Declare. + * emit-rtl.c (mem_attrs_eq_p): Export. + 2014-08-16 John David Anglin Backport from trunk: diff --git a/gcc/emit-rtl.c b/gcc/emit-rtl.c index b5278bf43186..1cac5181341f 100644 --- a/gcc/emit-rtl.c +++ b/gcc/emit-rtl.c @@ -263,7 +263,7 @@ mem_attrs_htab_hash (const void *x) /* Return true if the given memory attributes are equal. */ -static bool +bool mem_attrs_eq_p (const struct mem_attrs *p, const struct mem_attrs *q) { return (p->alias == q->alias diff --git a/gcc/emit-rtl.h b/gcc/emit-rtl.h index 726809097e78..81bb3344b58e 100644 --- a/gcc/emit-rtl.h +++ b/gcc/emit-rtl.h @@ -20,6 +20,9 @@ along with GCC; see the file COPYING3. If not see #ifndef GCC_EMIT_RTL_H #define GCC_EMIT_RTL_H +/* Return whether two MEM_ATTRs are equal. */ +bool mem_attrs_eq_p (const struct mem_attrs *, const struct mem_attrs *); + /* Set the alias set of MEM to SET. */ extern void set_mem_alias_set (rtx, alias_set_type); diff --git a/gcc/ifcvt.c b/gcc/ifcvt.c index e3353a5f26be..dd6df5bc80a6 100644 --- a/gcc/ifcvt.c +++ b/gcc/ifcvt.c @@ -294,6 +294,28 @@ block_fallthru (basic_block bb) return (e) ? e->dest : NULL_BLOCK; } + +/* Return true if RTXs A and B can be safely interchanged. */ + +static bool +rtx_interchangeable_p (const_rtx a, const_rtx b) +{ + if (!rtx_equal_p (a, b)) + return false; + + if (GET_CODE (a) != MEM) + return true; + + /* A dead type-unsafe memory reference is legal, but a live type-unsafe memory + reference is not. Interchanging a dead type-unsafe memory reference with + a live type-safe one creates a live type-unsafe memory reference, in other + words, it makes the program illegal. + We check here conservatively whether the two memory references have equal + memory attributes. */ + + return mem_attrs_eq_p (get_mem_attrs (a), get_mem_attrs (b)); +} + /* Go through a bunch of insns, converting them to conditional execution format if possible. Return TRUE if all of the non-note @@ -1014,6 +1036,9 @@ noce_try_move (struct noce_if_info *if_info) || (rtx_equal_p (if_info->a, XEXP (cond, 1)) && rtx_equal_p (if_info->b, XEXP (cond, 0)))) { + if (!rtx_interchangeable_p (if_info->a, if_info->b)) + return FALSE; + y = (code == EQ) ? if_info->a : if_info->b; /* Avoid generating the move if the source is the destination. */ @@ -2483,7 +2508,7 @@ noce_process_if_block (struct noce_if_info *if_info) if (! insn_b || insn_b != last_active_insn (else_bb, FALSE) || (set_b = single_set (insn_b)) == NULL_RTX - || ! rtx_equal_p (x, SET_DEST (set_b))) + || ! rtx_interchangeable_p (x, SET_DEST (set_b))) return FALSE; } else @@ -2496,7 +2521,7 @@ noce_process_if_block (struct noce_if_info *if_info) || BLOCK_FOR_INSN (insn_b) != BLOCK_FOR_INSN (if_info->cond_earliest) || !NONJUMP_INSN_P (insn_b) || (set_b = single_set (insn_b)) == NULL_RTX - || ! rtx_equal_p (x, SET_DEST (set_b)) + || ! rtx_interchangeable_p (x, SET_DEST (set_b)) || ! noce_operand_ok (SET_SRC (set_b)) || reg_overlap_mentioned_p (x, SET_SRC (set_b)) || modified_between_p (SET_SRC (set_b), insn_b, jump) @@ -2562,7 +2587,7 @@ noce_process_if_block (struct noce_if_info *if_info) /* Look and see if A and B are really the same. Avoid creating silly cmove constructs that no one will fix up later. */ - if (rtx_equal_p (a, b)) + if (rtx_interchangeable_p (a, b)) { /* If we have an INSN_B, we don't have to create any new rtl. Just move the instruction that we already have. If we don't have an diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 0a2ddbed3fa7..db8b656f83fd 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,14 @@ +2014-08-15 Tom de Vries + + Backport from mainline: + 2014-08-14 Tom de Vries + + PR rtl-optimization/62004 + PR rtl-optimization/62030 + * gcc.dg/pr62004.c: New test. + * gcc.dg/pr62030.c: Same. + * gcc.target/mips/pr62030-octeon.c: Same. + 2014-08-13 Felix Yang PR tree-optimization/62073 diff --git a/gcc/testsuite/gcc.dg/pr62004.c b/gcc/testsuite/gcc.dg/pr62004.c new file mode 100644 index 000000000000..c994a411b3b2 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr62004.c @@ -0,0 +1,47 @@ +/* { dg-do run } */ +/* { dg-options "-O2 -fno-tree-tail-merge" } */ + +struct node +{ + struct node *next; + struct node *prev; +}; + +struct node node; + +struct head +{ + struct node *first; +}; + +struct head heads[5]; + +int k = 2; + +struct head *head = &heads[2]; + +int +main () +{ + struct node *p; + + node.next = (void*)0; + + node.prev = (void *)head; + + head->first = &node; + + struct node *n = head->first; + + struct head *h = &heads[k]; + + heads[2].first = n->next; + + if ((void*)n->prev == (void *)h) + p = h->first; + else + /* Dead tbaa-unsafe load from ((struct node *)&heads[2])->next. */ + p = n->prev->next; + + return !(p == (void*)0); +} diff --git a/gcc/testsuite/gcc.dg/pr62030.c b/gcc/testsuite/gcc.dg/pr62030.c new file mode 100644 index 000000000000..b8baf934354c --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr62030.c @@ -0,0 +1,50 @@ +/* { dg-do run } */ +/* { dg-options "-O2" } */ + +extern void abort (void); + +struct node +{ + struct node *next; + struct node *prev; +}; + +struct node node; + +struct head +{ + struct node *first; +}; + +struct head heads[5]; + +int k = 2; + +struct head *head = &heads[2]; + +static int __attribute__((noinline)) +foo (void) +{ + node.prev = (void *)head; + head->first = &node; + + struct node *n = head->first; + struct head *h = &heads[k]; + struct node *next = n->next; + + if (n->prev == (void *)h) + h->first = next; + else + n->prev->next = next; + + n->next = h->first; + return n->next == &node; +} + +int +main (void) +{ + if (foo ()) + abort (); + return 0; +} diff --git a/gcc/testsuite/gcc.target/mips/pr62030-octeon.c b/gcc/testsuite/gcc.target/mips/pr62030-octeon.c new file mode 100644 index 000000000000..5e3d3b3b635e --- /dev/null +++ b/gcc/testsuite/gcc.target/mips/pr62030-octeon.c @@ -0,0 +1,50 @@ +/* { dg-do run } */ +/* { dg-options "-march=octeon" } */ + +extern void abort (void); + +struct node +{ + struct node *next; + struct node *prev; +}; + +struct node node; + +struct head +{ + struct node *first; +}; + +struct head heads[5]; + +int k = 2; + +struct head *head = &heads[2]; + +static int __attribute__((noinline)) +foo (void) +{ + node.prev = (void *)head; + head->first = &node; + + struct node *n = head->first; + struct head *h = &heads[k]; + struct node *next = n->next; + + if (n->prev == (void *)h) + h->first = next; + else + n->prev->next = next; + + n->next = h->first; + return n->next == &node; +} + +int +main (void) +{ + if (foo ()) + abort (); + return 0; +} -- 2.47.2