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[PATCH][ARM] PR/66433: Reduce cost of memory instructions with autoincrement


Hello!

Following patch fixes PR target/66433.

As described in PR, cost of memory operation with autoincrement is
considered to be greater than same operation without autoincrement. This
causes auto-inc-dec pass not to optimize vector memory operations like
vld and vst.

Bootstrapped and regtested on armv7l-linux-gnueabi on trunk.
OK for trunk?

--
BR,
Yury Usishchev

gcc/
2015-06-16  Yury Usishchev  <y.usishchev@samsung.com>

	PR target/66433
	* config/arm/arm.c (arm_new_rtx_costs): Reduce cost of memory instructions
	with autoincrement.

gcc/testsuite/
2015-06-16  Yury Usishchev  <y.usishchev@samsung.com>

	PR target/66433
	* gcc.target/arm/pr66433.c: New test.

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index f5050cb..a8dc0ed 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -9444,7 +9444,9 @@ arm_new_rtx_costs (rtx x, enum rtx_code code, enum rtx_code outer_code,
     case MEM:
       /* A memory access costs 1 insn if the mode is small, or the address is
 	 a single register, otherwise it costs one insn per word.  */
-      if (REG_P (XEXP (x, 0)))
+      if (REG_P (XEXP (x, 0))
+	  || (GET_RTX_CLASS (GET_CODE (XEXP (x, 0))) == RTX_AUTOINC
+	      && REG_P (XEXP (XEXP (x, 0), 0))))
 	*cost = COSTS_N_INSNS (1);
       else if (flag_pic
 	       && GET_CODE (XEXP (x, 0)) == PLUS
diff --git a/gcc/testsuite/gcc.target/arm/pr66433.c b/gcc/testsuite/gcc.target/arm/pr66433.c
new file mode 100644
index 0000000..22ba158
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr66433.c
@@ -0,0 +1,21 @@
+/* Test the optimization of `vld*' ARM NEON intrinsic with autoincrement. */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target arm_neon_ok } */
+/* { dg-options "-O2" } */
+/* { dg-add-options arm_neon } */
+
+#include <arm_neon.h>
+
+void test_vld_autoinc (uint32_t *__restrict__ a, uint32_t *__restrict__ b)
+{
+  int i;
+  for(i = 0; i < 1000000; i++) {
+    vst1q_u32 (b, vld1q_u32 (a));
+    a += 4;
+    b += 4;
+  }
+}
+
+/* { dg-final { scan-assembler "vld1\.32.*!.*\n" } } */
+/* { dg-final { scan-assembler "vst1\.32.*!.*\n" } } */

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