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[ARM] Use vector wide add for mixed-mode adds

Message ID 560267B4.5070809@arm.com
State New
Headers show

Commit Message

Kyrylo Tkachov Sept. 23, 2015, 8:49 a.m. UTC 
Hi Michael,

On 23/09/15 00:52, Michael Collison wrote:
> This is a modified version of the previous patch that removes the
> documentation and read-md.c fixes. These patches have been submitted
> separately and approved.
>
> This patch is designed to address code that was not being vectorized due
> to missing widening patterns in the ARM backend. Code such as:
>
> int t6(int len, void * dummy, short * __restrict x)
> {
>     len = len & ~31;
>     int result = 0;
>     __asm volatile ("");
>     for (int i = 0; i < len; i++)
>       result += x[i];
>     return result;
> }
>
> Validated on arm-none-eabi, arm-none-linux-gnueabi,
> arm-none-linux-gnueabihf, and armeb-none-linux-gnueabihf.
>
> 2015-09-22  Michael Collison  <michael.collison@linaro.org>
>
>       * config/arm/neon.md (widen_<us>sum<mode>): New patterns
>       where mode is VQI to improve mixed mode add vectorization.
>

Please list all the new define_expands and define_insns
in the changelog. Also, please add an ChangeLog entry for
the testsuite additions.

The approach looks ok to me with a few comments on some
parts of the patch itself.


+(define_insn "vec_sel_widen_ssum_hi<VQI:mode><VW:mode>3"
+  [(set (match_operand:<VW:V_widen> 0 "s_register_operand" "=w")
+	(plus:<VW:V_widen> (sign_extend:<VW:V_widen> (vec_select:VW (match_operand:VQI 1 "s_register_operand" "%w")
+						   (match_operand:VQI 2 "vect_par_constant_high" "")))
+		        (match_operand:<VW:V_widen> 3 "s_register_operand" "0")))]
+  "TARGET_NEON"
+  "vaddw.<V_s_elem>\t%q0, %q3, %f1"
+  [(set_attr "type" "neon_add_widen")
+  (set_attr "length" "8")]
+)


This is a single instruction, and it has a length of 4, so no need to override the length attribute.
Same with the other define_insns in this patch.


+/* { dg-final { scan-assembler "vaddw\.s16" } } */
+
+
+

Stray trailing newlines. Similar comments for the other testcases.

Thanks,
Kyrill
diff mbox

Patch

diff --git a/gcc/testsuite/gcc.target/arm/neon-vaddws16.c b/gcc/testsuite/gcc.target/arm/neon-vaddws16.c
new file mode 100644
index 0000000..ed10669
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/neon-vaddws16.c
@@ -0,0 +1,21 @@ 
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_neon_hw } */

The arm_neon_hw check is usually used when you want to run the tests.
Since this is a compile-only tests you just need arm_neon_ok.

  +/* { dg-add-options arm_neon_ok } */
+/* { dg-options "-O3" } */
+
+
+int
+t6(int len, void * dummy, short * __restrict x)
+{
+  len = len & ~31;
+  int result = 0;
+  __asm volatile ("");
+  for (int i = 0; i < len; i++)
+    result += x[i];
+  return result;
+}
+