From: Andrew Pinski <apin...@marvell.com> This is a new version of the patch to fix PR 102216. Instead of doing the canonicalization inside forwprop, Richi mentioned we should do it inside fold_stmt_1 and that is what this patch does.
PR tree-optimization/102216 gcc/ChangeLog: * gimple-fold.c (fold_stmt_1): Add canonicalization of "&MEM[ssa_n, CST]" to "ssa_n p+ CST", note this can only be done if !in_place. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/pr102216-1.C: New test. * g++.dg/tree-ssa/pr102216-2.C: New test. --- gcc/gimple-fold.c | 21 ++++++++++ gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C | 21 ++++++++++ gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C | 45 ++++++++++++++++++++++ 3 files changed, 87 insertions(+) create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c index ad9703ee471..aab6818c93f 100644 --- a/gcc/gimple-fold.c +++ b/gcc/gimple-fold.c @@ -6061,6 +6061,27 @@ fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace, tree (*valueize) (tree)) if (REFERENCE_CLASS_P (*lhs) && maybe_canonicalize_mem_ref_addr (lhs)) changed = true; + /* Canonicalize &MEM[ssa_n, CST] to ssa_n p+ CST. + This cannot be done in maybe_canonicalize_mem_ref_addr + as the gimple now has two operands rather than one. + The same reason why this can't be done in + maybe_canonicalize_mem_ref_addr is the same reason why + this can't be done inplace. */ + if (!inplace && TREE_CODE (*rhs) == ADDR_EXPR) + { + tree inner = TREE_OPERAND (*rhs, 0); + if (TREE_CODE (inner) == MEM_REF + && TREE_CODE (TREE_OPERAND (inner, 0)) == SSA_NAME + && TREE_CODE (TREE_OPERAND (inner, 1)) == INTEGER_CST) + { + tree ptr = TREE_OPERAND (inner, 0); + tree addon = TREE_OPERAND (inner, 1); + addon = fold_convert (sizetype, addon); + gimple_assign_set_rhs_with_ops (gsi, POINTER_PLUS_EXPR, + ptr, addon); + changed = true; + } + } } else { diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C b/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C new file mode 100644 index 00000000000..21f7f6797ff --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr102216-1.C @@ -0,0 +1,21 @@ +/* { dg-options "-O2 -fdump-tree-optimized" } */ +void link_error (); +void g () +{ + const char **language_names; + + language_names = new const char *[6]; + + const char **language_names_p = language_names; + + language_names_p++; + language_names_p++; + language_names_p++; + + if ( (language_names_p) - (language_names+3) != 0) + link_error(); + delete[] language_names; +} +/* We should have removed the link_error on the gimple level as GCC should + be able to tell that language_names_p is the same as language_names+3. */ +/* { dg-final { scan-tree-dump-times "link_error" 0 "optimized" } } */ diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C b/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C new file mode 100644 index 00000000000..8d351a9bad0 --- /dev/null +++ b/gcc/testsuite/g++.dg/tree-ssa/pr102216-2.C @@ -0,0 +1,45 @@ +/* { dg-options "-O2 -Wall" } */ +#include <algorithm> + +static inline bool +compare_cstrings (const char *str1, const char *str2) +{ + return str1 < str2; +} + +void +add_set_language_command () +{ + static const char **language_names; + + language_names = new const char *[6]; + + language_names[0] = "auto"; + language_names[1] = "local"; + language_names[2] = "unknown"; + + const char **language_names_p = language_names; + /* language_names_p == &language_names[0]. */ + language_names_p++; + /* language_names_p == &language_names[1]. */ + language_names_p++; + /* language_names_p == &language_names[2]. */ + language_names_p++; + /* language_names_p == &language_names[3]. */ + + const char **sort_begin; + + if (0) + sort_begin = &language_names[3]; + else + sort_begin = language_names_p; + + language_names[3] = ""; + language_names[4] = ""; + language_names[5] = NULL; + + /* There should be no warning associated with this std::sort as + sort_begin != &language_names[5] and GCC should be able to figure + that out. */ + std::sort (sort_begin, &language_names[5], compare_cstrings); +} -- 2.17.1