PR tree-ssa/54295

	* tree-ssa-math-opts.c (widening_mult_conversion_strippable_p):
	Sign-extension of a zero-extended value can be simplified to
	just zero-extension.

testsuite:
	* gcc.target/arm/pr50318-1.c: Scan for smlal.
	* gcc.target/arm/smlaltb-1.c: XFAIL test.
	* gcc.target/arm/smlaltt-1.c: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@191066 138bc75d-0d04-0410-961f-82ee72b054a4

6 files changed, 21 insertions, 4 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cdf6a201820..360fd5642fa 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2012-09-07  Richard Earnshaw  <rearnsha@arm.com>
+
+	PR tree-ssa/54295
+	* tree-ssa-math-opts.c (widening_mult_conversion_strippable_p):
+	Sign-extension of a zero-extended value can be simplified to
+	just zero-extension.
+
 2012-09-07  Richard Guenther  <rguenther@suse.de>
 
 	PR middle-end/53667
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8a987e1f8cf..ff3583fc525 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2012-09-07  Richard Earnshaw  <rearnsha@arm.com>
+
+	* gcc.target/arm/pr50318-1.c: Scan for smlal.
+	* gcc.target/arm/smlaltb-1.c: XFAIL test.
+	* gcc.target/arm/smlaltt-1.c: Likewise.
+
 2012-09-07  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gcc.dg/pr44194-1.c: Skip on Alpha and adjust regexp for SPARC64.
diff --git a/gcc/testsuite/gcc.target/arm/pr50318-1.c b/gcc/testsuite/gcc.target/arm/pr50318-1.c
index 05885e1b5ac..be270eefaef 100644
--- a/gcc/testsuite/gcc.target/arm/pr50318-1.c
+++ b/gcc/testsuite/gcc.target/arm/pr50318-1.c
@@ -8,4 +8,4 @@ long long test (unsigned int sec, unsigned long long nsecs)
    long)nsecs;
 }
 
-/* { dg-final { scan-assembler "umlal" } } */
+/* { dg-final { scan-assembler "smlal" } } */
diff --git a/gcc/testsuite/gcc.target/arm/smlaltb-1.c b/gcc/testsuite/gcc.target/arm/smlaltb-1.c
index 1472c9b3fa1..a27009d2513 100644
--- a/gcc/testsuite/gcc.target/arm/smlaltb-1.c
+++ b/gcc/testsuite/gcc.target/arm/smlaltb-1.c
@@ -11,4 +11,4 @@ foo (long long x, int in)
   return x + b * a;
 }
 
-/* { dg-final { scan-assembler "smlaltb\\t" } } */
+/* { dg-final { scan-assembler "smlaltb\\t" { xfail *-*-* } } } */
diff --git a/gcc/testsuite/gcc.target/arm/smlaltt-1.c b/gcc/testsuite/gcc.target/arm/smlaltt-1.c
index 6bcbce0b958..380e3d01be6 100644
--- a/gcc/testsuite/gcc.target/arm/smlaltt-1.c
+++ b/gcc/testsuite/gcc.target/arm/smlaltt-1.c
@@ -11,4 +11,4 @@ foo (long long x, int in1, int in2)
   return x + b * a;
 }
 
-/* { dg-final { scan-assembler "smlaltt\\t" } } */
+/* { dg-final { scan-assembler "smlaltt\\t" { xfail *-*-* } } } */
diff --git a/gcc/tree-ssa-math-opts.c b/gcc/tree-ssa-math-opts.c
index c3392fb14c8..94d19afc2c0 100644
--- a/gcc/tree-ssa-math-opts.c
+++ b/gcc/tree-ssa-math-opts.c
@@ -1985,7 +1985,11 @@ widening_mult_conversion_strippable_p (tree result_type, gimple stmt)
 	 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)
+      /* If the inner-most type is unsigned, then we can strip any
+	 intermediate widening operation.  If it's signed, then the
+	 intermediate widening operation must also be signed.  */
+      if ((TYPE_UNSIGNED (inner_op_type)
+	   || TYPE_UNSIGNED (op_type) == TYPE_UNSIGNED (inner_op_type))
 	  && TYPE_PRECISION (op_type) > TYPE_PRECISION (inner_op_type))
 	return true;