re PR rtl-optimization/89865 (FAIL: gcc.target/i386/pr49095.c scan-assembler-times \\\\), % 45)

	PR rtl-optimization/89865
	* config/i386/i386.md: Add peepholes for z = x; x ^= y; x != z.

	* gcc.target/i386/pr49095.c: Don't expect any RMW sequences.

From-SVN: r270206

4 files changed, 102 insertions, 4 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5ee20a9..5339017 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,6 +1,9 @@
 2019-04-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/89865
+	* config/i386/i386.md: Add peepholes for z = x; x ^= y; x != z.
+
+	PR rtl-optimization/89865
 	* config/i386/i386.md
 	(SWI12 peephole for mem {+,-,&,|,^}= x; mem != 0): Fix up operand
 	numbers not to clash with the additional operands[4].
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index b797e40..4188c1a 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -18931,6 +18931,100 @@
 		       const0_rtx);
 })
 
+;; Special cases for xor, where (x ^= y) != 0 is (misoptimized)
+;; into x = z; x ^= y; x != z
+(define_peephole2
+  [(set (match_operand:SWI 0 "register_operand")
+	(match_operand:SWI 1 "memory_operand"))
+   (set (match_operand:SWI 3 "register_operand") (match_dup 0))
+   (parallel [(set (match_operand:SWI 4 "register_operand")
+		   (xor:SWI (match_dup 4)
+			    (match_operand:SWI 2 "<nonmemory_operand>")))
+	      (clobber (reg:CC FLAGS_REG))])
+   (set (match_dup 1) (match_dup 4))
+   (set (reg:CCZ FLAGS_REG)
+	(compare:CCZ (match_operand:SWI 5 "register_operand")
+		     (match_operand:SWI 6 "<nonmemory_operand>")))]
+  "(TARGET_READ_MODIFY_WRITE || optimize_insn_for_size_p ())
+   && (REGNO (operands[4]) == REGNO (operands[0])
+       || REGNO (operands[4]) == REGNO (operands[3]))
+   && (rtx_equal_p (operands[REGNO (operands[4]) == REGNO (operands[0])
+			     ? 3 : 0], operands[5])
+       ? rtx_equal_p (operands[2], operands[6])
+       : rtx_equal_p (operands[2], operands[5])
+	 && rtx_equal_p (operands[REGNO (operands[4]) == REGNO (operands[0])
+				  ? 3 : 0], operands[6]))
+   && peep2_reg_dead_p (4, operands[4])
+   && peep2_reg_dead_p (5, operands[REGNO (operands[4]) == REGNO (operands[0])
+				    ? 3 : 0])
+   && !reg_overlap_mentioned_p (operands[0], operands[1])
+   && !reg_overlap_mentioned_p (operands[0], operands[2])
+   && !reg_overlap_mentioned_p (operands[3], operands[0])
+   && !reg_overlap_mentioned_p (operands[3], operands[1])
+   && !reg_overlap_mentioned_p (operands[3], operands[2])
+   && (<MODE>mode != QImode
+       || immediate_operand (operands[2], QImode)
+       || any_QIreg_operand (operands[2], QImode))"
+  [(parallel [(set (match_dup 7) (match_dup 9))
+	      (set (match_dup 1) (match_dup 8))])]
+{
+  operands[7] = SET_DEST (PATTERN (peep2_next_insn (4)));
+  operands[8] = gen_rtx_XOR (<MODE>mode, copy_rtx (operands[1]),
+			     operands[2]);
+  operands[9]
+    = gen_rtx_COMPARE (GET_MODE (operands[7]),
+		       copy_rtx (operands[8]),
+		       const0_rtx);
+})
+
+(define_peephole2
+  [(set (match_operand:SWI12 0 "register_operand")
+	(match_operand:SWI12 1 "memory_operand"))
+   (set (match_operand:SWI12 3 "register_operand") (match_dup 0))
+   (parallel [(set (match_operand:SI 4 "register_operand")
+		   (xor:SI (match_dup 4)
+			   (match_operand:SI 2 "<nonmemory_operand>")))
+	      (clobber (reg:CC FLAGS_REG))])
+   (set (match_dup 1) (match_operand:SWI12 5 "register_operand"))
+   (set (reg:CCZ FLAGS_REG)
+	(compare:CCZ (match_operand:SWI12 6 "register_operand")
+		     (match_operand:SWI12 7 "<nonmemory_operand>")))]
+  "(TARGET_READ_MODIFY_WRITE || optimize_insn_for_size_p ())
+   && (REGNO (operands[5]) == REGNO (operands[0])
+       || REGNO (operands[5]) == REGNO (operands[3]))
+   && REGNO (operands[5]) == REGNO (operands[4])
+   && (rtx_equal_p (operands[REGNO (operands[5]) == REGNO (operands[0])
+			     ? 3 : 0], operands[6])
+       ? (REG_P (operands[2])
+	  ? REG_P (operands[7]) && REGNO (operands[2]) == REGNO (operands[7])
+	  : rtx_equal_p (operands[2], operands[7]))
+       : (rtx_equal_p (operands[REGNO (operands[5]) == REGNO (operands[0])
+				? 3 : 0], operands[7])
+	  && REG_P (operands[2])
+	  && REGNO (operands[2]) == REGNO (operands[6])))
+   && peep2_reg_dead_p (4, operands[5])
+   && peep2_reg_dead_p (5, operands[REGNO (operands[5]) == REGNO (operands[0])
+				    ? 3 : 0])
+   && !reg_overlap_mentioned_p (operands[0], operands[1])
+   && !reg_overlap_mentioned_p (operands[0], operands[2])
+   && !reg_overlap_mentioned_p (operands[3], operands[0])
+   && !reg_overlap_mentioned_p (operands[3], operands[1])
+   && !reg_overlap_mentioned_p (operands[3], operands[2])
+   && (<MODE>mode != QImode
+       || immediate_operand (operands[2], SImode)
+       || any_QIreg_operand (operands[2], SImode))"
+  [(parallel [(set (match_dup 8) (match_dup 10))
+	      (set (match_dup 1) (match_dup 9))])]
+{
+  operands[8] = SET_DEST (PATTERN (peep2_next_insn (4)));
+  operands[9] = gen_rtx_XOR (<MODE>mode, copy_rtx (operands[1]),
+			     gen_lowpart (<MODE>mode, operands[2]));
+  operands[10]
+    = gen_rtx_COMPARE (GET_MODE (operands[8]),
+		       copy_rtx (operands[9]),
+		       const0_rtx);
+})
+
 ;; Attempt to optimize away memory stores of values the memory already
 ;; has.  See PR79593.
 (define_peephole2
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 087c58b..9b7b08d 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,9 @@
 2019-04-08  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/89865
+	* gcc.target/i386/pr49095.c: Don't expect any RMW sequences.
+
+	PR rtl-optimization/89865
 	* gcc.target/i386/pr49095.c: Adjust number of expected RMW spots
 	on ia32.
 
diff --git a/gcc/testsuite/gcc.target/i386/pr49095.c b/gcc/testsuite/gcc.target/i386/pr49095.c
index 3ae14e3..f1295b3 100644
--- a/gcc/testsuite/gcc.target/i386/pr49095.c
+++ b/gcc/testsuite/gcc.target/i386/pr49095.c
@@ -71,7 +71,5 @@ G (int)
 G (long)
 
 /* { dg-final { scan-assembler-not "test\[lq\]" } } */
-/* The {f,h}{char,short,int,long}xor functions aren't optimized into
-   a RMW instruction, so need load, modify and store.  FIXME eventually.  */
-/* { dg-final { scan-assembler-times "\\(%eax\\), %" 8 { target { ia32 } } } } */
-/* { dg-final { scan-assembler-times "\\(%\[re\]di\\), %" 8 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-not "\\(%eax\\), %" { target { ia32 } } } } */
+/* { dg-final { scan-assembler-not "\\(%\[re\]di\\), %" { target { ! ia32 } } } } */