From 72d50660ad57224cefc7ad40b81c994b49a503b6 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Wed, 8 Jun 2016 13:11:43 +0000 Subject: [PATCH] re PR tree-optimization/71452 (Wrong optimization of stores to _Bool via char*) 2016-06-08 Richard Biener PR tree-optimization/71452 * tree-ssa.c (non_rewritable_lvalue_p): Make sure that the type used for the SSA rewrite has enough precision to cover the dynamic type of the location. * gcc.dg/torture/pr71452.c: New testcase. From-SVN: r237214 --- gcc/ChangeLog | 7 +++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/torture/pr71452.c | 10 ++++++++++ gcc/tree-ssa.c | 8 ++++++++ 4 files changed, 30 insertions(+) create mode 100644 gcc/testsuite/gcc.dg/torture/pr71452.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6ad6ddc5b90..4f5d3177f1e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2016-06-08 Richard Biener + + PR tree-optimization/71452 + * tree-ssa.c (non_rewritable_lvalue_p): Make sure that the + type used for the SSA rewrite has enough precision to cover + the dynamic type of the location. + 2016-06-08 Jakub Jelinek Richard Biener diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index d8b668cfaab..28b17cf4d02 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2016-06-08 Richard Biener + + PR tree-optimization/71452 + * gcc.dg/torture/pr71452.c: New testcase. + 2016-06-08 Jakub Jelinek PR c++/71448 diff --git a/gcc/testsuite/gcc.dg/torture/pr71452.c b/gcc/testsuite/gcc.dg/torture/pr71452.c new file mode 100644 index 00000000000..8948d39fdaf --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr71452.c @@ -0,0 +1,10 @@ +/* { dg-do run } */ + +int main() +{ + _Bool b; + *(char *)&b = 123; + if (*(char *)&b != 123) + __builtin_abort (); + return 0; +} diff --git a/gcc/tree-ssa.c b/gcc/tree-ssa.c index 2f3caf341dd..30c6269e345 100644 --- a/gcc/tree-ssa.c +++ b/gcc/tree-ssa.c @@ -1292,6 +1292,14 @@ non_rewritable_lvalue_p (tree lhs) if (integer_zerop (TREE_OPERAND (lhs, 1)) && DECL_P (decl) && DECL_SIZE (decl) == TYPE_SIZE (TREE_TYPE (lhs)) + /* If the dynamic type of the decl has larger precision than + the decl itself we can't use the decls type for SSA rewriting. */ + && ((! INTEGRAL_TYPE_P (TREE_TYPE (decl)) + || compare_tree_int (DECL_SIZE (decl), + TYPE_PRECISION (TREE_TYPE (decl))) == 0) + || (INTEGRAL_TYPE_P (TREE_TYPE (lhs)) + && (TYPE_PRECISION (TREE_TYPE (decl)) + >= TYPE_PRECISION (TREE_TYPE (lhs))))) && (TREE_THIS_VOLATILE (decl) == TREE_THIS_VOLATILE (lhs))) return false; -- 2.30.2