This fixes another case where re-constructing ARRAY_REFs that were not in the IL produced by the frontend produces bogus IL. This time an ICE only, but in other cases this results in wrong-code because of constraints we impose on ARRAY_REFs in data-dependence analysis for example.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk. Richard. 2012-08-10 Richard Guenther <rguent...@suse.de> PR tree-optimization/54109 * tree-ssa-forwprop.c (forward_propagate_addr_into_variable_array_index): Remove. (forward_propagate_addr_expr_1): Adjust. * gcc.dg/torture/pr54109.c: New testcase. * gcc.dg/tree-ssa/forwprop-1.c: Adjust. * gcc.dg/tree-ssa/forwprop-2.c: Likewise. Index: trunk/gcc/testsuite/gcc.dg/torture/pr54109.c =================================================================== *** /dev/null 1970-01-01 00:00:00.000000000 +0000 --- trunk/gcc/testsuite/gcc.dg/torture/pr54109.c 2012-08-09 16:21:12.145568259 +0200 *************** *** 0 **** --- 1,29 ---- + /* { dg-do compile } */ + + typedef struct + { + unsigned long bits[4]; + } nodemask_t; + + struct cpuset + { + long flags; + nodemask_t mems_allowed; + struct cpuset *parent; + } b; + + void func1(unsigned long *p1, int p2) + { + p1[p2 - 1] = 0; + } + + void func2(nodemask_t *p1, int p2) + { + func1(p1->bits, p2); + } + + void func3(void) + { + /* This accesses b.flags. */ + func2(&b.mems_allowed, 0); + } Index: trunk/gcc/tree-ssa-forwprop.c =================================================================== *** trunk.orig/gcc/tree-ssa-forwprop.c 2012-08-09 16:20:28.000000000 +0200 --- trunk/gcc/tree-ssa-forwprop.c 2012-08-09 16:21:12.147568259 +0200 *************** tidy_after_forward_propagate_addr (gimpl *** 697,824 **** recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt)); } - /* DEF_RHS contains the address of the 0th element in an array. - USE_STMT uses type of DEF_RHS to compute the address of an - arbitrary element within the array. The (variable) byte offset - of the element is contained in OFFSET. - - We walk back through the use-def chains of OFFSET to verify that - it is indeed computing the offset of an element within the array - and extract the index corresponding to the given byte offset. - - We then try to fold the entire address expression into a form - &array[index]. - - If we are successful, we replace the right hand side of USE_STMT - with the new address computation. */ - - static bool - forward_propagate_addr_into_variable_array_index (tree offset, - tree def_rhs, - gimple_stmt_iterator *use_stmt_gsi) - { - tree index, tunit; - gimple offset_def, use_stmt = gsi_stmt (*use_stmt_gsi); - tree new_rhs, tmp; - - if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF) - tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (def_rhs))); - else if (TREE_CODE (TREE_TYPE (TREE_OPERAND (def_rhs, 0))) == ARRAY_TYPE) - tunit = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs)))); - else - return false; - if (!host_integerp (tunit, 1)) - return false; - - /* Get the offset's defining statement. */ - offset_def = SSA_NAME_DEF_STMT (offset); - - /* Try to find an expression for a proper index. This is either a - multiplication expression by the element size or just the ssa name we came - along in case the element size is one. In that case, however, we do not - allow multiplications because they can be computing index to a higher - level dimension (PR 37861). */ - if (integer_onep (tunit)) - { - if (is_gimple_assign (offset_def) - && gimple_assign_rhs_code (offset_def) == MULT_EXPR) - return false; - - index = offset; - } - else - { - /* The statement which defines OFFSET before type conversion - must be a simple GIMPLE_ASSIGN. */ - if (!is_gimple_assign (offset_def)) - return false; - - /* The RHS of the statement which defines OFFSET must be a - multiplication of an object by the size of the array elements. - This implicitly verifies that the size of the array elements - is constant. */ - if (gimple_assign_rhs_code (offset_def) == MULT_EXPR - && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST - && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), tunit)) - { - /* The first operand to the MULT_EXPR is the desired index. */ - index = gimple_assign_rhs1 (offset_def); - } - /* If we have idx * tunit + CST * tunit re-associate that. */ - else if ((gimple_assign_rhs_code (offset_def) == PLUS_EXPR - || gimple_assign_rhs_code (offset_def) == MINUS_EXPR) - && TREE_CODE (gimple_assign_rhs1 (offset_def)) == SSA_NAME - && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST - && (tmp = div_if_zero_remainder (EXACT_DIV_EXPR, - gimple_assign_rhs2 (offset_def), - tunit)) != NULL_TREE) - { - gimple offset_def2 = SSA_NAME_DEF_STMT (gimple_assign_rhs1 (offset_def)); - if (is_gimple_assign (offset_def2) - && gimple_assign_rhs_code (offset_def2) == MULT_EXPR - && TREE_CODE (gimple_assign_rhs2 (offset_def2)) == INTEGER_CST - && tree_int_cst_equal (gimple_assign_rhs2 (offset_def2), tunit)) - { - index = fold_build2 (gimple_assign_rhs_code (offset_def), - TREE_TYPE (offset), - gimple_assign_rhs1 (offset_def2), tmp); - } - else - return false; - } - else - return false; - } - - /* Replace the pointer addition with array indexing. */ - index = force_gimple_operand_gsi (use_stmt_gsi, index, true, NULL_TREE, - true, GSI_SAME_STMT); - if (TREE_CODE (TREE_OPERAND (def_rhs, 0)) == ARRAY_REF) - { - new_rhs = unshare_expr (def_rhs); - TREE_OPERAND (TREE_OPERAND (new_rhs, 0), 1) = index; - } - else - { - new_rhs = build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (TREE_TYPE (def_rhs))), - unshare_expr (TREE_OPERAND (def_rhs, 0)), - index, integer_zero_node, NULL_TREE); - new_rhs = build_fold_addr_expr (new_rhs); - if (!useless_type_conversion_p (TREE_TYPE (gimple_assign_lhs (use_stmt)), - TREE_TYPE (new_rhs))) - { - new_rhs = force_gimple_operand_gsi (use_stmt_gsi, new_rhs, true, - NULL_TREE, true, GSI_SAME_STMT); - new_rhs = fold_convert (TREE_TYPE (gimple_assign_lhs (use_stmt)), - new_rhs); - } - } - gimple_assign_set_rhs_from_tree (use_stmt_gsi, new_rhs); - fold_stmt (use_stmt_gsi); - tidy_after_forward_propagate_addr (gsi_stmt (*use_stmt_gsi)); - return true; - } - /* NAME is a SSA_NAME representing DEF_RHS which is of the form ADDR_EXPR <whatever>. --- 697,702 ---- *************** forward_propagate_addr_expr_1 (tree name *** 1111,1129 **** return true; } - /* Try to optimize &x[0] p+ OFFSET where OFFSET is defined by - converting a multiplication of an index by the size of the - array elements, then the result is converted into the proper - type for the arithmetic. */ - if (TREE_CODE (rhs2) == SSA_NAME - && (TREE_CODE (array_ref) != ARRAY_REF - || integer_zerop (TREE_OPERAND (array_ref, 1))) - && useless_type_conversion_p (TREE_TYPE (name), TREE_TYPE (def_rhs)) - /* Avoid problems with IVopts creating PLUS_EXPRs with a - different type than their operands. */ - && useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (def_rhs))) - return forward_propagate_addr_into_variable_array_index (rhs2, def_rhs, - use_stmt_gsi); return false; } --- 989,994 ---- Index: trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-1.c =================================================================== *** trunk.orig/gcc/testsuite/gcc.dg/tree-ssa/forwprop-1.c 2010-07-01 10:55:03.000000000 +0200 --- trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-1.c 2012-08-09 16:25:48.666558686 +0200 *************** *** 1,8 **** /* { dg-do compile } */ /* { dg-options "-O2 -fdump-tree-forwprop1" } */ ! /* We should be able to optimize this to b->t[i] = 1 during ! early optimizations. */ struct a { --- 1,7 ---- /* { dg-do compile } */ /* { dg-options "-O2 -fdump-tree-forwprop1" } */ ! /* We may not optimize this to b->t[i] = 1. */ struct a { *************** void f(struct a * b, __SIZE_TYPE__ i) *** 15,19 **** c[i] = 1; } ! /* { dg-final { scan-tree-dump-times "t\\\[i.*\\\].* = 1;" 1 "forwprop1" } } */ /* { dg-final { cleanup-tree-dump "forwprop1" } } */ --- 14,18 ---- c[i] = 1; } ! /* { dg-final { scan-tree-dump-times "\\\[\[^\n\r\]*\\\] = 1;" 0 "forwprop1" } } */ /* { dg-final { cleanup-tree-dump "forwprop1" } } */ Index: trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-2.c =================================================================== *** trunk.orig/gcc/testsuite/gcc.dg/tree-ssa/forwprop-2.c 2010-07-01 10:55:03.000000000 +0200 --- trunk/gcc/testsuite/gcc.dg/tree-ssa/forwprop-2.c 2012-08-09 16:26:38.180557015 +0200 *************** *** 1,8 **** /* { dg-do compile } */ /* { dg-options "-O2 -fdump-tree-forwprop1" } */ ! /* We should be able to optimize this to b->t[i] = 1 during ! early optimizations. */ struct a { --- 1,7 ---- /* { dg-do compile } */ /* { dg-options "-O2 -fdump-tree-forwprop1" } */ ! /* We may not optimize this to b->t[i] = 1. */ struct a { *************** void f(__SIZE_TYPE__ i) *** 17,21 **** c[i] = 1; } ! /* { dg-final { scan-tree-dump-times "t\\\[i.*\\\].* = 1;" 1 "forwprop1" } } */ /* { dg-final { cleanup-tree-dump "forwprop?" } } */ --- 16,20 ---- c[i] = 1; } ! /* { dg-final { scan-tree-dump-times "\\\[\[^\n\r\]*\\\] = 1;" 0 "forwprop1" } } */ /* { dg-final { cleanup-tree-dump "forwprop?" } } */