From 05f9c67507bd614e1fa1e5184a855a8257bc04fe Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 19 Nov 2014 09:18:53 +0100
Subject: [PATCH] re PR rtl-optimization/63843 (wrong code generation at -O1
 and higher)

	PR rtl-optimization/63843
	* simplify-rtx.c (simplify_binary_operation_1) <case ASHIFTRT>: For
	optimization of ashiftrt of subreg of lshiftrt, check that code
	is ASHIFTRT.

	* gcc.c-torture/execute/pr63843.c: New test.

From-SVN: r217753
---
 gcc/ChangeLog                                 |  7 ++
 gcc/simplify-rtx.c                            | 73 +++++++++----------
 gcc/testsuite/ChangeLog                       |  5 ++
 gcc/testsuite/gcc.c-torture/execute/pr63843.c | 31 ++++++++
 4 files changed, 79 insertions(+), 37 deletions(-)
 create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr63843.c

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7dcfba38c5a..b1bb78ffb0e 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2014-11-19  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/63843
+	* simplify-rtx.c (simplify_binary_operation_1) <case ASHIFTRT>: For
+	optimization of ashiftrt of subreg of lshiftrt, check that code
+	is ASHIFTRT.
+
 2014-11-18  Andrew MacLeod  <amacleod@redhat.com>
 
 	* attribs.c (decl_attributes): Remove always true condition,
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 8094c7584ac..022e36fe7c0 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -3105,43 +3105,42 @@ simplify_binary_operation_1 (enum rtx_code code, machine_mode mode,
 	  && ! side_effects_p (op1))
 	return op0;
       /* Given:
-         scalar modes M1, M2
-         scalar constants c1, c2
-         size (M2) > size (M1)
-         c1 == size (M2) - size (M1)
-         optimize:
-         (ashiftrt:M1 (subreg:M1 (lshiftrt:M2 (reg:M2)
-                                              (const_int <c1>))
-                                  <low_part>)
-                      (const_int <c2>))
-         to:
-         (subreg:M1 (ashiftrt:M2 (reg:M2)
-                                 (const_int <c1 + c2>))
-          <low_part>).  */
-      if (!VECTOR_MODE_P (mode)
-          && SUBREG_P (op0)
-          && CONST_INT_P (op1)
-          && (GET_CODE (SUBREG_REG (op0)) == LSHIFTRT)
-          && !VECTOR_MODE_P (GET_MODE (SUBREG_REG (op0)))
-          && CONST_INT_P (XEXP (SUBREG_REG (op0), 1))
-          && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
-              > GET_MODE_BITSIZE (mode))
-          && (INTVAL (XEXP (SUBREG_REG (op0), 1))
-              == (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
-                  - GET_MODE_BITSIZE (mode)))
-          && subreg_lowpart_p (op0))
-        {
-          rtx tmp = GEN_INT (INTVAL (XEXP (SUBREG_REG (op0), 1))
-                             + INTVAL (op1));
-          machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
-          tmp = simplify_gen_binary (ASHIFTRT,
-                                     GET_MODE (SUBREG_REG (op0)),
-                                     XEXP (SUBREG_REG (op0), 0),
-                                     tmp);
-          return simplify_gen_subreg (mode, tmp, inner_mode,
-                                      subreg_lowpart_offset (mode,
-                                                             inner_mode));
-        }
+	 scalar modes M1, M2
+	 scalar constants c1, c2
+	 size (M2) > size (M1)
+	 c1 == size (M2) - size (M1)
+	 optimize:
+	 (ashiftrt:M1 (subreg:M1 (lshiftrt:M2 (reg:M2) (const_int <c1>))
+				 <low_part>)
+		      (const_int <c2>))
+	 to:
+	 (subreg:M1 (ashiftrt:M2 (reg:M2) (const_int <c1 + c2>))
+		    <low_part>).  */
+      if (code == ASHIFTRT
+	  && !VECTOR_MODE_P (mode)
+	  && SUBREG_P (op0)
+	  && CONST_INT_P (op1)
+	  && GET_CODE (SUBREG_REG (op0)) == LSHIFTRT
+	  && !VECTOR_MODE_P (GET_MODE (SUBREG_REG (op0)))
+	  && CONST_INT_P (XEXP (SUBREG_REG (op0), 1))
+	  && (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
+	      > GET_MODE_BITSIZE (mode))
+	  && (INTVAL (XEXP (SUBREG_REG (op0), 1))
+	      == (GET_MODE_BITSIZE (GET_MODE (SUBREG_REG (op0)))
+		  - GET_MODE_BITSIZE (mode)))
+	  && subreg_lowpart_p (op0))
+	{
+	  rtx tmp = GEN_INT (INTVAL (XEXP (SUBREG_REG (op0), 1))
+			     + INTVAL (op1));
+	  machine_mode inner_mode = GET_MODE (SUBREG_REG (op0));
+	  tmp = simplify_gen_binary (ASHIFTRT,
+				     GET_MODE (SUBREG_REG (op0)),
+				     XEXP (SUBREG_REG (op0), 0),
+				     tmp);
+	  return simplify_gen_subreg (mode, tmp, inner_mode,
+				      subreg_lowpart_offset (mode,
+							     inner_mode));
+	}
     canonicalize_shift:
       if (SHIFT_COUNT_TRUNCATED && CONST_INT_P (op1))
 	{
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1a56e1ac9ed..118805c26e1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-11-19  Jakub Jelinek  <jakub@redhat.com>
+
+	PR rtl-optimization/63843
+	* gcc.c-torture/execute/pr63843.c: New test.
+
 2014-11-18  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	PR target/63937
diff --git a/gcc/testsuite/gcc.c-torture/execute/pr63843.c b/gcc/testsuite/gcc.c-torture/execute/pr63843.c
new file mode 100644
index 00000000000..9f6c7b06c39
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr63843.c
@@ -0,0 +1,31 @@
+/* PR rtl-optimization/63843 */
+
+static inline __attribute__ ((always_inline))
+unsigned short foo (unsigned short v)
+{
+  return (v << 8) | (v >> 8);
+}
+
+unsigned short __attribute__ ((noinline, noclone, hot))
+bar (unsigned char *x)
+{
+  unsigned int a;
+  unsigned short b;
+  __builtin_memcpy (&a, &x[0], sizeof (a));
+  a ^= 0x80808080U;
+  __builtin_memcpy (&x[0], &a, sizeof (a));
+  __builtin_memcpy (&b, &x[2], sizeof (b));
+  return foo (b);
+}
+
+int
+main ()
+{
+  unsigned char x[8] = { 0x01, 0x01, 0x01, 0x01 };
+  if (__CHAR_BIT__ == 8
+      && sizeof (short) == 2
+      && sizeof (int) == 4
+      && bar (x) != 0x8181U)
+    __builtin_abort ();
+  return 0;
+}
-- 
2.30.2