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author | Richard Earnshaw <rearnsha@arm.com> | 2012-08-20 12:49:47 +0000 |
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committer | Richard Earnshaw <rearnsha@gcc.gnu.org> | 2012-08-20 12:49:47 +0000 |
commit | 7ab6a8280170732268c190fffb7f522c73f7b800 (patch) | |
tree | 974542ce1cddb8b6e57104203aaa61a2f96f6fcb /gcc | |
parent | 19f757838959f060042c2db6c6dee79a930dfa5c (diff) | |
download | gcc-7ab6a8280170732268c190fffb7f522c73f7b800.zip gcc-7ab6a8280170732268c190fffb7f522c73f7b800.tar.gz gcc-7ab6a8280170732268c190fffb7f522c73f7b800.tar.bz2 |
re PR tree-optimization/54295 (Widening multiply-accumulate operation uses wrong value extension)
PR tree-ssa/54295
* tree-ssa-math-opts.c (widening_mult_conversion_strippable_p):
New function.
(is_widening_mult_rhs_p): Use it.
* gcc.c-torture/execute/20120817-1.c: New test.
From-SVN: r190533
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/ChangeLog | 7 | ||||
-rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
-rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/20120817-1.c | 14 | ||||
-rw-r--r-- | gcc/tree-ssa-math-opts.c | 41 |
4 files changed, 64 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f892f00..13e2b4c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2012-08-20 Richard Earnshaw <rearnsha@arm.com> + + 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 <joseph@codesourcery.com> * configure.ac (ffs): Check for declaration. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e9aaf24..f33149a 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2012-08-20 Richard Earnshaw <rearnsha@arm.com> + PR tree-ssa/54295 + * gcc.c-torture/execute/20120817-1.c: New test. + +2012-08-20 Richard Earnshaw <rearnsha@arm.com> + * gcc.target/arm/thumb-16bit-ops.c (f): This test uses a 16-bit add instruction. (f2): New test that really does need adds. 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 0000000..8fb2820 --- /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 0d6eeb6..748bf2f 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 { |