This fixes PR52548, we were not flow-sensitively pruning EXP_GEN
sets during antic-in computation. Fixed by simply pruning EXP_GEN
at generation time.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2012-03-22 Richard Guenther <rguent...@suse.de>
PR tree-optimization/52548
* tree-ssa-pre.c (valid_in_sets): Remove handling of invalidation
because of clobbers.
(prune_clobbered_mems): New function.
(compute_antic_aux): Use it to prune ANTIC_OUT.
(compute_partial_antic_aux): Use it to prune PA_IN.
(compute_avail): Only insert expressions into EXP_GEN that
are not invalidated when translated up to the beginning of
the block.
* gcc.dg/tree-ssa/ssa-pre-29.c: New testcase.
Index: gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-29.c
===================================================================
*** gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-29.c (revision 0)
--- gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-29.c (revision 0)
***************
*** 0 ****
--- 1,21 ----
+ /* { dg-do compile } */
+ /* { dg-options "-O2 -fdump-tree-pre-details" } */
+
+ int flag, hoist, y, z;
+
+ void
+ foo (void)
+ {
+ if (flag)
+ y = hoist + 4;
+ else
+ flag = 888;
+ z = hoist + 4;
+ bark ();
+ }
+
+ /* We should see the partial redundancy of hoist + 4, not being confused
+ about bark () possibly clobbering hoist. */
+
+ /* { dg-final { scan-tree-dump "Replaced hoist" "pre" } } */
+ /* { dg-final { cleanup-tree-dump "pre" } } */
Index: gcc/tree-ssa-pre.c
===================================================================
*** gcc/tree-ssa-pre.c (revision 185680)
--- gcc/tree-ssa-pre.c (working copy)
*************** valid_in_sets (bitmap_set_t set1, bitmap
*** 2123,2138 ****
if (!vro_valid_in_sets (set1, set2, vro))
return false;
}
! if (ref->vuse)
! {
! gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
! if (!gimple_nop_p (def_stmt)
! && gimple_bb (def_stmt) != block
! && !dominated_by_p (CDI_DOMINATORS,
! block, gimple_bb (def_stmt)))
! return false;
! }
! return !value_dies_in_block_x (expr, block);
}
default:
gcc_unreachable ();
--- 2123,2129 ----
if (!vro_valid_in_sets (set1, set2, vro))
return false;
}
! return true;
}
default:
gcc_unreachable ();
*************** clean (bitmap_set_t set, basic_block blo
*** 2179,2184 ****
--- 2170,2207 ----
VEC_free (pre_expr, heap, exprs);
}
+ /* Clean the set of expressions that are no longer valid in SET because
+ they are clobbered in BLOCK. */
+
+ static void
+ prune_clobbered_mems (bitmap_set_t set, basic_block block)
+ {
+ VEC (pre_expr, heap) *exprs = sorted_array_from_bitmap_set (set);
+ pre_expr expr;
+ int i;
+
+ FOR_EACH_VEC_ELT (pre_expr, exprs, i, expr)
+ {
+ vn_reference_t ref;
+ if (expr->kind != REFERENCE)
+ continue;
+
+ ref = PRE_EXPR_REFERENCE (expr);
+ if (ref->vuse)
+ {
+ gimple def_stmt = SSA_NAME_DEF_STMT (ref->vuse);
+ if (!gimple_nop_p (def_stmt)
+ && ((gimple_bb (def_stmt) != block
+ && !dominated_by_p (CDI_DOMINATORS,
+ block, gimple_bb (def_stmt)))
+ || (gimple_bb (def_stmt) == block
+ && value_dies_in_block_x (expr, block))))
+ bitmap_remove_from_set (set, expr);
+ }
+ }
+ VEC_free (pre_expr, heap, exprs);
+ }
+
static sbitmap has_abnormal_preds;
/* List of blocks that may have changed during ANTIC computation and
*************** compute_antic_aux (basic_block block, bo
*** 2320,2325 ****
--- 2343,2352 ----
VEC_free (basic_block, heap, worklist);
}
+ /* Prune expressions that are clobbered in block and thus become
+ invalid if translated from ANTIC_OUT to ANTIC_IN. */
+ prune_clobbered_mems (ANTIC_OUT, block);
+
/* Generate ANTIC_OUT - TMP_GEN. */
S = bitmap_set_subtract (ANTIC_OUT, TMP_GEN (block));
*************** compute_partial_antic_aux (basic_block b
*** 2474,2479 ****
--- 2501,2510 ----
VEC_free (basic_block, heap, worklist);
}
+ /* Prune expressions that are clobbered in block and thus become
+ invalid if translated from PA_OUT to PA_IN. */
+ prune_clobbered_mems (PA_OUT, block);
+
/* PA_IN starts with PA_OUT - TMP_GEN.
Then we subtract things from ANTIC_IN. */
PA_IN (block) = bitmap_set_subtract (PA_OUT, TMP_GEN (block));
*************** compute_avail (void)
*** 4027,4041 ****
if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
add_to_exp_gen (block, vro->op2);
}
! result = (pre_expr) pool_alloc (pre_expr_pool);
! result->kind = REFERENCE;
! result->id = 0;
! PRE_EXPR_REFERENCE (result) = ref;
!
! get_or_alloc_expression_id (result);
! add_to_value (get_expr_value_id (result), result);
! if (!in_fre)
! bitmap_value_insert_into_set (EXP_GEN (block), result);
continue;
}
--- 4058,4083 ----
if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
add_to_exp_gen (block, vro->op2);
}
!
! /* If the value of the call is not invalidated in
! this block until it is computed, add the expression
! to EXP_GEN. */
! if (!gimple_vuse (stmt)
! || gimple_code
! (SSA_NAME_DEF_STMT (gimple_vuse (stmt))) == GIMPLE_PHI
! || gimple_bb (SSA_NAME_DEF_STMT
! (gimple_vuse (stmt))) != block)
! {
! result = (pre_expr) pool_alloc (pre_expr_pool);
! result->kind = REFERENCE;
! result->id = 0;
! PRE_EXPR_REFERENCE (result) = ref;
!
! get_or_alloc_expression_id (result);
! add_to_value (get_expr_value_id (result), result);
! if (!in_fre)
! bitmap_value_insert_into_set (EXP_GEN (block), result);
! }
continue;
}
*************** compute_avail (void)
*** 4095,4100 ****
--- 4137,4168 ----
if (vro->op2 && TREE_CODE (vro->op2) == SSA_NAME)
add_to_exp_gen (block, vro->op2);
}
+
+ /* If the value of the reference is not invalidated in
+ this block until it is computed, add the expression
+ to EXP_GEN. */
+ if (gimple_vuse (stmt))
+ {
+ gimple def_stmt;
+ bool ok = true;
+ def_stmt = SSA_NAME_DEF_STMT (gimple_vuse (stmt));
+ while (!gimple_nop_p (def_stmt)
+ && gimple_code (def_stmt) != GIMPLE_PHI
+ && gimple_bb (def_stmt) == block)
+ {
+ if (stmt_may_clobber_ref_p
+ (def_stmt, gimple_assign_rhs1 (stmt)))
+ {
+ ok = false;
+ break;
+ }
+ def_stmt
+ = SSA_NAME_DEF_STMT (gimple_vuse (def_stmt));
+ }
+ if (!ok)
+ continue;
+ }
+
result = (pre_expr) pool_alloc (pre_expr_pool);
result->kind = REFERENCE;
result->id = 0;
