diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f892f00f2b7f..13e2b4c719e9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2012-08-20 Richard Earnshaw + + PR tree-ssa/54295 + * tree-ssa-math-opts.c (widening_mult_conversion_strippable_p): + New function. + (is_widening_mult_rhs_p): Use it. + 2012-08-20 Joseph Myers * configure.ac (ffs): Check for declaration. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e9aaf243950c..f33149ae1b69 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2012-08-20 Richard Earnshaw + + PR tree-ssa/54295 + * gcc.c-torture/execute/20120817-1.c: New test. + 2012-08-20 Richard Earnshaw * gcc.target/arm/thumb-16bit-ops.c (f): This test uses a 16-bit diff --git a/gcc/testsuite/gcc.c-torture/execute/20120817-1.c b/gcc/testsuite/gcc.c-torture/execute/20120817-1.c new file mode 100644 index 000000000000..8fb2820e8966 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/20120817-1.c @@ -0,0 +1,14 @@ +typedef unsigned long long u64; +unsigned long foo = 0; +u64 f() __attribute__((noinline)); + +u64 f() { + return ((u64)40) + ((u64) 24) * (int)(foo - 1); +} + +int main () +{ + if (f () != 16) + abort (); + exit (0); +} diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c index 0d6eeb69055f..748bf2f1e496 100644 --- a/gcc/tree-ssa-math-opts.c +++ b/gcc/tree-ssa-math-opts.c @@ -1958,6 +1958,43 @@ struct gimple_opt_pass pass_optimize_bswap = } }; +/* Return true if stmt is a type conversion operation that can be stripped + when used in a widening multiply operation. */ +static bool +widening_mult_conversion_strippable_p (tree result_type, gimple stmt) +{ + enum tree_code rhs_code = gimple_assign_rhs_code (stmt); + + if (TREE_CODE (result_type) == INTEGER_TYPE) + { + tree op_type; + tree inner_op_type; + + if (!CONVERT_EXPR_CODE_P (rhs_code)) + return false; + + op_type = TREE_TYPE (gimple_assign_lhs (stmt)); + + /* If the type of OP has the same precision as the result, then + we can strip this conversion. The multiply operation will be + selected to create the correct extension as a by-product. */ + if (TYPE_PRECISION (result_type) == TYPE_PRECISION (op_type)) + return true; + + /* We can also strip a conversion if it preserves the signed-ness of + the operation and doesn't narrow the range. */ + inner_op_type = TREE_TYPE (gimple_assign_rhs1 (stmt)); + + if (TYPE_UNSIGNED (op_type) == TYPE_UNSIGNED (inner_op_type) + && TYPE_PRECISION (op_type) > TYPE_PRECISION (inner_op_type)) + return true; + + return false; + } + + return rhs_code == FIXED_CONVERT_EXPR; +} + /* Return true if RHS is a suitable operand for a widening multiplication, assuming a target type of TYPE. There are two cases: @@ -1982,9 +2019,7 @@ is_widening_mult_rhs_p (tree type, tree rhs, tree *type_out, if (is_gimple_assign (stmt)) { rhs_code = gimple_assign_rhs_code (stmt); - if (TREE_CODE (type) == INTEGER_TYPE - ? !CONVERT_EXPR_CODE_P (rhs_code) - : rhs_code != FIXED_CONVERT_EXPR) + if (! widening_mult_conversion_strippable_p (type, stmt)) rhs1 = rhs; else {