[AArch64][v2] Improve comparison with complex immediates followed by branch/cset

	* config/aarch64/aarch64.md (*condjump): Rename to...
	(condjump): ... This.
	(*compare_condjump<mode>): New define_insn_and_split.
	(*compare_cstore<mode>_insn): Likewise.
	(*cstore<mode>_insn): Rename to...
	(cstore<mode>_insn): ... This.
	* config/aarch64/iterators.md (CMP): Handle ne code.
	* config/aarch64/predicates.md (aarch64_imm24): New predicate.

	* gcc.target/aarch64/cmpimm_branch_1.c: New test.
	* gcc.target/aarch64/cmpimm_cset_1.c: Likewise.

From-SVN: r230805

7 files changed, 143 insertions, 3 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 02590a2..ada1e30 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2015-11-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* config/aarch64/aarch64.md (*condjump): Rename to...
+	(condjump): ... This.
+	(*compare_condjump<mode>): New define_insn_and_split.
+	(*compare_cstore<mode>_insn): Likewise.
+	(*cstore<mode>_insn): Rename to...
+	(cstore<mode>_insn): ... This.
+	* config/aarch64/iterators.md (CMP): Handle ne code.
+	* config/aarch64/predicates.md (aarch64_imm24): New predicate.
+
 2015-11-24  Mikhail Maltsev  <maltsevm@gmail.com>
 
 	PR target/68497
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index d46f837..28a7f8c 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -376,7 +376,7 @@
   }
 )
 
-(define_insn "*condjump"
+(define_insn "condjump"
   [(set (pc) (if_then_else (match_operator 0 "aarch64_comparison_operator"
 			    [(match_operand 1 "cc_register" "") (const_int 0)])
 			   (label_ref (match_operand 2 "" ""))
@@ -401,6 +401,41 @@
 		      (const_int 1)))]
 )
 
+;; For a 24-bit immediate CST we can optimize the compare for equality
+;; and branch sequence from:
+;; 	mov	x0, #imm1
+;; 	movk	x0, #imm2, lsl 16 /* x0 contains CST.  */
+;; 	cmp	x1, x0
+;; 	b<ne,eq> .Label
+;; into the shorter:
+;; 	sub	x0, x1, #(CST & 0xfff000)
+;; 	subs	x0, x0, #(CST & 0x000fff)
+;; 	b<ne,eq> .Label
+(define_insn_and_split "*compare_condjump<mode>"
+  [(set (pc) (if_then_else (EQL
+			      (match_operand:GPI 0 "register_operand" "r")
+			      (match_operand:GPI 1 "aarch64_imm24" "n"))
+			   (label_ref:P (match_operand 2 "" ""))
+			   (pc)))]
+  "!aarch64_move_imm (INTVAL (operands[1]), <MODE>mode)
+   && !aarch64_plus_operand (operands[1], <MODE>mode)
+   && !reload_completed"
+  "#"
+  "&& true"
+  [(const_int 0)]
+  {
+    HOST_WIDE_INT lo_imm = UINTVAL (operands[1]) & 0xfff;
+    HOST_WIDE_INT hi_imm = UINTVAL (operands[1]) & 0xfff000;
+    rtx tmp = gen_reg_rtx (<MODE>mode);
+    emit_insn (gen_add<mode>3 (tmp, operands[0], GEN_INT (-hi_imm)));
+    emit_insn (gen_add<mode>3_compare0 (tmp, tmp, GEN_INT (-lo_imm)));
+    rtx cc_reg = gen_rtx_REG (CC_NZmode, CC_REGNUM);
+    rtx cmp_rtx = gen_rtx_fmt_ee (<EQL:CMP>, <MODE>mode, cc_reg, const0_rtx);
+    emit_jump_insn (gen_condjump (cmp_rtx, cc_reg, operands[2]));
+    DONE;
+  }
+)
+
 (define_expand "casesi"
   [(match_operand:SI 0 "register_operand" "")	; Index
    (match_operand:SI 1 "const_int_operand" "")	; Lower bound
@@ -2905,7 +2940,7 @@
   "
 )
 
-(define_insn "*cstore<mode>_insn"
+(define_insn "aarch64_cstore<mode>"
   [(set (match_operand:ALLI 0 "register_operand" "=r")
 	(match_operator:ALLI 1 "aarch64_comparison_operator"
 	 [(match_operand 2 "cc_register" "") (const_int 0)]))]
@@ -2914,6 +2949,40 @@
   [(set_attr "type" "csel")]
 )
 
+;; For a 24-bit immediate CST we can optimize the compare for equality
+;; and branch sequence from:
+;; 	mov	x0, #imm1
+;; 	movk	x0, #imm2, lsl 16 /* x0 contains CST.  */
+;; 	cmp	x1, x0
+;; 	cset	x2, <ne,eq>
+;; into the shorter:
+;; 	sub	x0, x1, #(CST & 0xfff000)
+;; 	subs	x0, x0, #(CST & 0x000fff)
+;; 	cset x2, <ne, eq>.
+(define_insn_and_split "*compare_cstore<mode>_insn"
+  [(set (match_operand:GPI 0 "register_operand" "=r")
+	 (EQL:GPI (match_operand:GPI 1 "register_operand" "r")
+		  (match_operand:GPI 2 "aarch64_imm24" "n")))]
+  "!aarch64_move_imm (INTVAL (operands[2]), <MODE>mode)
+   && !aarch64_plus_operand (operands[2], <MODE>mode)
+   && !reload_completed"
+  "#"
+  "&& true"
+  [(const_int 0)]
+  {
+    HOST_WIDE_INT lo_imm = UINTVAL (operands[2]) & 0xfff;
+    HOST_WIDE_INT hi_imm = UINTVAL (operands[2]) & 0xfff000;
+    rtx tmp = gen_reg_rtx (<MODE>mode);
+    emit_insn (gen_add<mode>3 (tmp, operands[1], GEN_INT (-hi_imm)));
+    emit_insn (gen_add<mode>3_compare0 (tmp, tmp, GEN_INT (-lo_imm)));
+    rtx cc_reg = gen_rtx_REG (CC_NZmode, CC_REGNUM);
+    rtx cmp_rtx = gen_rtx_fmt_ee (<EQL:CMP>, <MODE>mode, cc_reg, const0_rtx);
+    emit_insn (gen_aarch64_cstore<mode> (operands[0], cmp_rtx, cc_reg));
+    DONE;
+  }
+  [(set_attr "type" "csel")]
+)
+
 ;; zero_extend version of the above
 (define_insn "*cstoresi_insn_uxtw"
   [(set (match_operand:DI 0 "register_operand" "=r")
diff --git a/gcc/config/aarch64/iterators.md b/gcc/config/aarch64/iterators.md
index c2eb7de..422bc87 100644
--- a/gcc/config/aarch64/iterators.md
+++ b/gcc/config/aarch64/iterators.md
@@ -824,7 +824,8 @@
 			   (ltu "1") (leu "1") (geu "2") (gtu "2")])
 
 (define_code_attr CMP [(lt "LT") (le "LE") (eq "EQ") (ge "GE") (gt "GT")
-			   (ltu "LTU") (leu "LEU") (geu "GEU") (gtu "GTU")])
+			(ltu "LTU") (leu "LEU") (ne "NE") (geu "GEU")
+			(gtu "GTU")])
 
 (define_code_attr fix_trunc_optab [(fix "fix_trunc")
 				   (unsigned_fix "fixuns_trunc")])
diff --git a/gcc/config/aarch64/predicates.md b/gcc/config/aarch64/predicates.md
index e7f76e0..c0c3ff5 100644
--- a/gcc/config/aarch64/predicates.md
+++ b/gcc/config/aarch64/predicates.md
@@ -145,6 +145,11 @@
   (and (match_code "const_int")
        (match_test "(unsigned HOST_WIDE_INT) INTVAL (op) <= 4")))
 
+;; An immediate that fits into 24 bits.
+(define_predicate "aarch64_imm24"
+  (and (match_code "const_int")
+       (match_test "IN_RANGE (UINTVAL (op), 0, 0xffffff)")))
+
 (define_predicate "aarch64_pwr_imm3"
   (and (match_code "const_int")
        (match_test "INTVAL (op) != 0
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3ec74df..47f7ea5 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-11-24  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	* gcc.target/aarch64/cmpimm_branch_1.c: New test.
+	* gcc.target/aarch64/cmpimm_cset_1.c: Likewise.
+
 2015-11-24  Mikhail Maltsev  <maltsevm@gmail.com>
 
 	PR target/68497
diff --git a/gcc/testsuite/gcc.target/aarch64/cmpimm_branch_1.c b/gcc/testsuite/gcc.target/aarch64/cmpimm_branch_1.c
new file mode 100644
index 0000000..7ad736b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/cmpimm_branch_1.c
@@ -0,0 +1,26 @@
+/* { dg-do compile } */
+/* { dg-options "-save-temps -O2" } */
+
+/* Test that we emit a sub+subs sequence rather than mov+movk+cmp.  */
+
+void g (void);
+void
+foo (int x)
+{
+  if (x != 0x123456)
+    g ();
+}
+
+void
+fool (long long x)
+{
+  if (x != 0x123456)
+    g ();
+}
+
+/* { dg-final { scan-assembler-not "cmp\tw\[0-9\]*.*" } } */
+/* { dg-final { scan-assembler-not "cmp\tx\[0-9\]*.*" } } */
+/* { dg-final { scan-assembler-times "sub\tw\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "sub\tx\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "subs\tw\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "subs\tx\[0-9\]+.*" 1 } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/cmpimm_cset_1.c b/gcc/testsuite/gcc.target/aarch64/cmpimm_cset_1.c
new file mode 100644
index 0000000..f6fd69f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/cmpimm_cset_1.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-save-temps -O2" } */
+
+/* Test that we emit a sub+subs sequence rather than mov+movk+cmp.  */
+
+int
+foo (int x)
+{
+  return x == 0x123456;
+}
+
+long long
+fool (long long x)
+{
+  return x == 0x123456;
+}
+
+/* { dg-final { scan-assembler-not "cmp\tw\[0-9\]*.*" } } */
+/* { dg-final { scan-assembler-not "cmp\tx\[0-9\]*.*" } } */
+/* { dg-final { scan-assembler-times "sub\tw\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "sub\tx\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "subs\tw\[0-9\]+.*" 1 } } */
+/* { dg-final { scan-assembler-times "subs\tx\[0-9\]+.*" 1 } } */