[AArch64] Fix wrong-code bug in right-shift SISD patterns

	* config/aarch64/aarch64.md (*aarch64_lshr_sisd_or_int_<mode>3):
	Mark operand 0 as earlyclobber in 2nd alternative.
	(1st define_split below *aarch64_lshr_sisd_or_int_<mode>3):
	Write negated shift amount into QI lowpart operand 0 and use it
	in the shift step.
	(2nd define_split below *aarch64_lshr_sisd_or_int_<mode>3): Likewise.

	* gcc.target/aarch64/sisd-shft-neg_1.c: New test.

From-SVN: r220860

4 files changed, 62 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a899997..32cc757 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2015-02-20  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/aarch64.md (*aarch64_lshr_sisd_or_int_<mode>3):
+	Mark operand 0 as earlyclobber in 2nd alternative.
+	(1st define_split below *aarch64_lshr_sisd_or_int_<mode>3):
+	Write negated shift amount into QI lowpart operand 0 and use it
+	in the shift step.
+	(2nd define_split below *aarch64_lshr_sisd_or_int_<mode>3): Likewise.
+
 2015-02-20  Bernd Schmidt  <bernds@codesourcery.com>
 
     	* cgraph.h (clone_function_name_1): Declare.
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 1f4169e..8f157ce2 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -3360,7 +3360,7 @@
 
 ;; Logical right shift using SISD or Integer instruction
 (define_insn "*aarch64_lshr_sisd_or_int_<mode>3"
-  [(set (match_operand:GPI 0 "register_operand" "=w,w,r")
+  [(set (match_operand:GPI 0 "register_operand" "=w,&w,r")
         (lshiftrt:GPI
           (match_operand:GPI 1 "register_operand" "w,w,r")
           (match_operand:QI 2 "aarch64_reg_or_shift_imm_<mode>" "Us<cmode>,w,rUs<cmode>")))]
@@ -3379,11 +3379,13 @@
            (match_operand:DI 1 "aarch64_simd_register")
            (match_operand:QI 2 "aarch64_simd_register")))]
   "TARGET_SIMD && reload_completed"
-  [(set (match_dup 2)
+  [(set (match_dup 3)
         (unspec:QI [(match_dup 2)] UNSPEC_SISD_NEG))
    (set (match_dup 0)
-        (unspec:DI [(match_dup 1) (match_dup 2)] UNSPEC_SISD_USHL))]
-  ""
+        (unspec:DI [(match_dup 1) (match_dup 3)] UNSPEC_SISD_USHL))]
+  {
+    operands[3] = gen_lowpart (QImode, operands[0]);
+  }
 )
 
 (define_split
@@ -3392,11 +3394,13 @@
            (match_operand:SI 1 "aarch64_simd_register")
            (match_operand:QI 2 "aarch64_simd_register")))]
   "TARGET_SIMD && reload_completed"
-  [(set (match_dup 2)
+  [(set (match_dup 3)
         (unspec:QI [(match_dup 2)] UNSPEC_SISD_NEG))
    (set (match_dup 0)
-        (unspec:SI [(match_dup 1) (match_dup 2)] UNSPEC_USHL_2S))]
-  ""
+        (unspec:SI [(match_dup 1) (match_dup 3)] UNSPEC_USHL_2S))]
+  {
+    operands[3] = gen_lowpart (QImode, operands[0]);
+  }
 )
 
 ;; Arithmetic right shift using SISD or Integer instruction
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 2409cfb..65310fd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-02-20  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* gcc.target/aarch64/sisd-shft-neg_1.c: New test.
+
 2015-02-20  Georg-Johann Lay  <avr@gjlay.de>
 
 	PR target/64452
diff --git a/gcc/testsuite/gcc.target/aarch64/sisd-shft-neg_1.c b/gcc/testsuite/gcc.target/aarch64/sisd-shft-neg_1.c
new file mode 100644
index 0000000..c091657
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sisd-shft-neg_1.c
@@ -0,0 +1,38 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-inline" } */
+
+extern void abort (void);
+
+#define force_simd_si(v) asm volatile ("mov %s0, %1.s[0]" :"=w" (v) :"w" (v) :)
+
+unsigned int
+shft_add (unsigned int a, unsigned int b)
+{
+  unsigned int c;
+
+  force_simd_si (a);
+  force_simd_si (b);
+  c = a >> b;
+  force_simd_si (c);
+
+  return c + b;
+}
+
+int
+main (void)
+{
+  unsigned int i = 0;
+  unsigned int a = 0xdeadbeef;
+
+  for (i = 0; i < 32; i++)
+  {
+    unsigned int exp = (a / (1 << i) + i);
+    unsigned int got = shft_add (a, i);
+
+    if (exp != got)
+      abort ();
+  }
+
+  return 0;
+}
+