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[PATCH (8/7)] Fix a bug in multiply-and-accumulate
- From: Andrew Stubbs <ams at codesourcery dot com>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 18 Jul 2011 14:14:05 +0100
- Subject: [PATCH (8/7)] Fix a bug in multiply-and-accumulate
- References: <4E034EF2.3070503@codesourcery.com>
As far as I can tell, the patch series so far works great as long as the
input type of the accumulate value is the same as the output type.
Unfortunately you get an ICE otherwise .... doh!
This patch should fix the problem.
I could have inserted this fix into the correct spot in the existing
series, but I've already regenerated the whole lot several times, it's
getting confusing, and they're all approved already, so I'm just going
to tack this one on the end.
Andrew
2011-07-18 Andrew Stubbs <ams@codesourcery.com>
gcc/
* tree-ssa-math-opts.c (convert_plusminus_to_widen): Convert add_rhs
to the correct type.
gcc/testsuite/
* gcc.target/arm/wmul-10.c: New file.
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/wmul-10.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=armv7-a" } */
+
+unsigned long long
+foo (unsigned short a, unsigned short *b, unsigned short *c)
+{
+ return (unsigned)a + (unsigned long long)*b * (unsigned long long)*c;
+}
+
+/* { dg-final { scan-assembler "umlal" } } */
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -2375,6 +2375,10 @@ convert_plusminus_to_widen (gimple_stmt_iterator *gsi, gimple stmt,
mult_rhs2 = build_and_insert_cast (gsi, loc, tmp, mult_rhs2);
}
+ if (TYPE_PRECISION (type) != TYPE_PRECISION (TREE_TYPE (add_rhs)))
+ add_rhs = build_and_insert_cast (gsi, loc, create_tmp_var (type, NULL),
+ add_rhs);
+
gimple_assign_set_rhs_with_ops_1 (gsi, wmult_code, mult_rhs1, mult_rhs2,
add_rhs);
update_stmt (gsi_stmt (*gsi));