arm.h (TARGET_HAVE_CBZ): Define.

2016-07-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>

    gcc/
    * config/arm/arm.h (TARGET_HAVE_CBZ): Define.
    (TARGET_IDIV): Set for all Thumb targets provided they have hardware
    divide feature.
    * config/arm/arm.md (divsi3): New unpredicable alternative for ARMv8-M
    Baseline.  Make initial alternative TARGET_32BIT only.
    (udivsi3): Likewise.
    * config/arm/thumb1.md (thumb1_cbz): New define_insn.
    * doc/sourcebuild.texi (arm_thumb1_cbz_ok): Document new effective
    target.

    gcc/testsuite/
    * lib/target-supports.exp (check_effective_target_arm_thumb1_cbz_ok):
    Add new arm_thumb1_cbz_ok effective target.
    * gcc.target/arm/cbz.c: New test.

From-SVN: r238289

8 files changed, 156 insertions, 11 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3f7e7f1..f05d2b1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,17 @@
 2016-07-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
+	* config/arm/arm.h (TARGET_HAVE_CBZ): Define.
+	(TARGET_IDIV): Set for all Thumb targets provided they have hardware
+	divide feature.
+	* config/arm/arm.md (divsi3): New unpredicable alternative for ARMv8-M
+	Baseline.  Make initial alternative TARGET_32BIT only.
+	(udivsi3): Likewise.
+	* config/arm/thumb1.md (thumb1_cbz): New define_insn.
+	* doc/sourcebuild.texi (arm_thumb1_cbz_ok): Document new effective
+	target.
+
+2016-07-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
 	* config/arm/arm.h (TARGET_HAVE_MOVT): Include ARMv8-M as having MOVT.
 	* config/arm/arm.c (arm_arch_name): (const_ok_for_op): Check MOVT/MOVW
 	availability with TARGET_HAVE_MOVT.
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index 6a0f645..317885c 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -266,9 +266,12 @@ extern void (*arm_lang_output_object_attributes_hook)(void);
 /* Nonzero if this chip provides the MOVW and MOVT instructions.  */
 #define TARGET_HAVE_MOVT	(arm_arch_thumb2 || arm_arch8)
 
+/* Nonzero if this chip provides the CBZ and CBNZ instructions.  */
+#define TARGET_HAVE_CBZ		(arm_arch_thumb2 || arm_arch8)
+
 /* Nonzero if integer division instructions supported.  */
 #define TARGET_IDIV	((TARGET_ARM && arm_arch_arm_hwdiv)	\
-			 || (TARGET_THUMB2 && arm_arch_thumb_hwdiv))
+			 || (TARGET_THUMB && arm_arch_thumb_hwdiv))
 
 /* Nonzero if disallow volatile memory access in IT block.  */
 #define TARGET_NO_VOLATILE_CE		(arm_arch_no_volatile_ce)
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 8727c6d..8204715 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -4330,23 +4330,29 @@
 
 ;; Division instructions
 (define_insn "divsi3"
-  [(set (match_operand:SI	  0 "s_register_operand" "=r")
-	(div:SI (match_operand:SI 1 "s_register_operand"  "r")
-		(match_operand:SI 2 "s_register_operand"  "r")))]
+  [(set (match_operand:SI	  0 "s_register_operand" "=r,r")
+	(div:SI (match_operand:SI 1 "s_register_operand"  "r,r")
+		(match_operand:SI 2 "s_register_operand"  "r,r")))]
   "TARGET_IDIV"
-  "sdiv%?\t%0, %1, %2"
-  [(set_attr "predicable" "yes")
+  "@
+   sdiv%?\t%0, %1, %2
+   sdiv\t%0, %1, %2"
+  [(set_attr "arch" "32,v8mb")
+   (set_attr "predicable" "yes")
    (set_attr "predicable_short_it" "no")
    (set_attr "type" "sdiv")]
 )
 
 (define_insn "udivsi3"
-  [(set (match_operand:SI	   0 "s_register_operand" "=r")
-	(udiv:SI (match_operand:SI 1 "s_register_operand"  "r")
-		 (match_operand:SI 2 "s_register_operand"  "r")))]
+  [(set (match_operand:SI	   0 "s_register_operand" "=r,r")
+	(udiv:SI (match_operand:SI 1 "s_register_operand"  "r,r")
+		 (match_operand:SI 2 "s_register_operand"  "r,r")))]
   "TARGET_IDIV"
-  "udiv%?\t%0, %1, %2"
-  [(set_attr "predicable" "yes")
+  "@
+   udiv%?\t%0, %1, %2
+   udiv\t%0, %1, %2"
+  [(set_attr "arch" "32,v8mb")
+   (set_attr "predicable" "yes")
    (set_attr "predicable_short_it" "no")
    (set_attr "type" "udiv")]
 )
diff --git a/gcc/config/arm/thumb1.md b/gcc/config/arm/thumb1.md
index b317f1b..cd98de7 100644
--- a/gcc/config/arm/thumb1.md
+++ b/gcc/config/arm/thumb1.md
@@ -974,6 +974,91 @@
   DONE;
 })
 
+;; A pattern for the CB(N)Z instruction added in ARMv8-M Baseline profile,
+;; adapted from cbranchsi4_insn.  Modifying cbranchsi4_insn instead leads to
+;; code generation difference for ARMv6-M because the minimum length of the
+;; instruction becomes 2 even for ARMv6-M due to a limitation in genattrtab's
+;; handling of PC in the length condition.
+(define_insn "thumb1_cbz"
+  [(set (pc) (if_then_else
+	      (match_operator 0 "equality_operator"
+	       [(match_operand:SI 1 "s_register_operand" "l")
+		(const_int 0)])
+	      (label_ref (match_operand 2 "" ""))
+	      (pc)))]
+  "TARGET_THUMB1 && TARGET_HAVE_CBZ"
+{
+  if (get_attr_length (insn) == 2)
+    {
+      if (GET_CODE (operands[0]) == EQ)
+	return "cbz\t%1, %l2";
+      else
+	return "cbnz\t%1, %l2";
+    }
+  else
+    {
+      rtx t = cfun->machine->thumb1_cc_insn;
+      if (t != NULL_RTX)
+	{
+	  if (!rtx_equal_p (cfun->machine->thumb1_cc_op0, operands[1])
+	      || !rtx_equal_p (cfun->machine->thumb1_cc_op1, operands[2]))
+	    t = NULL_RTX;
+	  if (cfun->machine->thumb1_cc_mode == CC_NOOVmode)
+	    {
+	      if (!noov_comparison_operator (operands[0], VOIDmode))
+		t = NULL_RTX;
+	    }
+	  else if (cfun->machine->thumb1_cc_mode != CCmode)
+	    t = NULL_RTX;
+	}
+      if (t == NULL_RTX)
+	{
+	  output_asm_insn ("cmp\t%1, #0", operands);
+	  cfun->machine->thumb1_cc_insn = insn;
+	  cfun->machine->thumb1_cc_op0 = operands[1];
+	  cfun->machine->thumb1_cc_op1 = operands[2];
+	  cfun->machine->thumb1_cc_mode = CCmode;
+	}
+      else
+	/* Ensure we emit the right type of condition code on the jump.  */
+	XEXP (operands[0], 0) = gen_rtx_REG (cfun->machine->thumb1_cc_mode,
+					     CC_REGNUM);
+
+      switch (get_attr_length (insn))
+	{
+	case 4:  return "b%d0\t%l2";
+	case 6:  return "b%D0\t.LCB%=;b\t%l2\t%@long jump\n.LCB%=:";
+	case 8:  return "b%D0\t.LCB%=;bl\t%l2\t%@far jump\n.LCB%=:";
+	default: gcc_unreachable ();
+	}
+    }
+}
+  [(set (attr "far_jump")
+	(if_then_else
+	    (eq_attr "length" "8")
+	    (const_string "yes")
+	    (const_string "no")))
+   (set (attr "length")
+	(if_then_else
+	    (and (ge (minus (match_dup 2) (pc)) (const_int 2))
+		 (le (minus (match_dup 2) (pc)) (const_int 128)))
+	    (const_int 2)
+	    (if_then_else
+		(and (ge (minus (match_dup 2) (pc)) (const_int -250))
+		     (le (minus (match_dup 2) (pc)) (const_int 256)))
+		(const_int 4)
+		(if_then_else
+		    (and (ge (minus (match_dup 2) (pc)) (const_int -2040))
+			 (le (minus (match_dup 2) (pc)) (const_int 2048)))
+		    (const_int 6)
+		    (const_int 8)))))
+   (set (attr "type")
+	(if_then_else
+	    (eq_attr "length" "2")
+	    (const_string "branch")
+	    (const_string "multiple")))]
+)
+
 (define_insn "cbranchsi4_insn"
   [(set (pc) (if_then_else
 	      (match_operator 0 "arm_comparison_operator"
diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index b437c17..24b65da 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -1618,6 +1618,10 @@ ARM target prefers @code{LDRD} and @code{STRD} instructions over
 ARM target generates Thumb-1 code for @code{-mthumb} with @code{MOVW}
 and @code{MOVT} instructions available.
 
+@item arm_thumb1_cbz_ok
+ARM target generates Thumb-1 code for @code{-mthumb} with
+@code{CBZ} and @code{CBNZ} instructions available.
+
 @end table
 
 @subsubsection AArch64-specific attributes
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d1204e7..239d55e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2016-07-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>
 
+	* lib/target-supports.exp (check_effective_target_arm_thumb1_cbz_ok):
+	Add new arm_thumb1_cbz_ok effective target.
+	* gcc.target/arm/cbz.c: New test.
+
+2016-07-13  Thomas Preud'homme  <thomas.preudhomme@arm.com>
+
 	* lib/target-supports.exp (check_effective_target_arm_thumb1_movt_ok):
 	Define effective target.
 	* gcc.target/arm/pr42574.c: Require arm_thumb1_ok and
diff --git a/gcc/testsuite/gcc.target/arm/cbz.c b/gcc/testsuite/gcc.target/arm/cbz.c
new file mode 100644
index 0000000..5d3de63
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/cbz.c
@@ -0,0 +1,12 @@
+/* { dg-do compile {target { arm_thumb2 || arm_thumb1_cbz_ok } } } */
+/* { dg-options "-O2" } */
+
+int
+foo (int a, int *b)
+{
+  if (a)
+    *b = 1;
+  return 0;
+}
+
+/* { dg-final { scan-assembler-times "cbz\\tr\\d" 1 } } */
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index e6a1170..b9909ad 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -3502,6 +3502,23 @@ proc check_effective_target_arm_thumb1_movt_ok {} {
     }
 }
 
+# Return 1 if this is an ARM target where -mthumb causes Thumb-1 to be
+# used and CBZ and CBNZ instructions are available.
+
+proc check_effective_target_arm_thumb1_cbz_ok {} {
+    if [check_effective_target_arm_thumb1_ok] {
+	return [check_no_compiler_messages arm_movt object {
+	    int
+	    foo (void)
+	    {
+	      asm ("cbz r0, 2f\n2:");
+	    }
+	} "-mthumb"]
+    } else {
+	return 0
+    }
+}
+
 # Return 1 if this compilation turns on string_ops_prefer_neon on.
 
 proc check_effective_target_arm_tune_string_ops_prefer_neon { } {