[PATCH 5/6] [ARC] Fix unwanted match for sign extend 16-bit constant.

[Claudiu Zissulescu]

The combine pass may conclude umulhisi3_imm pattern can accept also sign
extended 16-bit constants. This patch prohibits the combine in considering
this pattern as suitable.

OK to apply?
Claudiu

gcc/
2016-04-18  Claudiu Zissulescu  <claz...@synopsys.com>

        * config/arc/arc.md (umulhisi3_imm): Avoid unwanted match for sign
        extend 16-bit constants.
        * testsuite/gcc.target/arc/umulsihi3_z.c: New file.
---
 gcc/config/arc/arc.md                      |  3 ++-
 gcc/testsuite/gcc.target/arc/umulsihi3_z.c | 23 +++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/arc/umulsihi3_z.c

diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md
index 74530b1..6731072 100644
--- a/gcc/config/arc/arc.md
+++ b/gcc/config/arc/arc.md
@@ -1729,7 +1729,8 @@
 (define_insn "umulhisi3_imm"
   [(set (match_operand:SI 0 "register_operand"                          "=r, 
r,r,  r,  r")
        (mult:SI (zero_extend:SI (match_operand:HI 1 "register_operand" " 0, 
r,0,  0,  r"))
-                (match_operand:HI 2 "short_const_int_operand"          " L, 
L,I,C16,C16")))]
+                (match_operand:HI 2 "short_const_int_operand"          " L, 
L,I,C16,C16")))
+  (use (match_dup 2))]
   "TARGET_MPYW"
   "mpyuw%? %0,%1,%2"
   [(set_attr "length" "4,4,4,8,8")
diff --git a/gcc/testsuite/gcc.target/arc/umulsihi3_z.c 
b/gcc/testsuite/gcc.target/arc/umulsihi3_z.c
new file mode 100644
index 0000000..cf1c00d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arc/umulsihi3_z.c
@@ -0,0 +1,23 @@
+/* Check if the optimizers are not removing the umulsihi3_imm
+   instruction.  */
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-inline" } */
+
+#include <stdint.h>
+
+static int32_t test (int16_t reg_val)
+{
+  int32_t x = (reg_val & 0xf) * 62500;
+  return x;
+}
+
+int main (void)
+{
+  volatile int32_t x = 0xc172;
+  x = test (x);
+
+  if (x != 0x0001e848)
+    __builtin_abort ();
+  return 0;
+}
+
-- 
1.9.1