[PATCH, i386]: Fix PR 91385, Zero-extended negation is not generated

[Uros Bizjak]

It looks that combine lost some of its unwanted creativity. Added
testcase will keep it that way.

2019-08-07  Uroš Bizjak  <ubizjak@gmail.com>

    PR target/91385
    * config/i386/sse.md (*negsi2_1_zext): Simplify insn pattern.
    (*negsi2_cmpz_zext): Ditto.

testsuite/ChangeLog:

2019-08-07  Uroš Bizjak  <ubizjak@gmail.com>

    PR target/91385
    * gcc.target/i386/pr91385.c: New test.

Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.

Committed to mainline SVN.

Uros.
-------------- next part --------------
Index: config/i386/i386.md
===================================================================
--- config/i386/i386.md	(revision 274169)
+++ config/i386/i386.md	(working copy)
@@ -9337,13 +9337,10 @@
   [(set_attr "type" "negnot")
    (set_attr "mode" "<MODE>")])
 
-;; Combine is quite creative about this pattern.
 (define_insn "*negsi2_1_zext"
   [(set (match_operand:DI 0 "register_operand" "=r")
-	(lshiftrt:DI
-	  (neg:DI (ashift:DI (match_operand:DI 1 "register_operand" "0")
-			     (const_int 32)))
-	(const_int 32)))
+	(zero_extend:DI
+	  (neg:SI (match_operand:SI 1 "register_operand" "0"))))
    (clobber (reg:CC FLAGS_REG))]
   "TARGET_64BIT && ix86_unary_operator_ok (NEG, SImode, operands)"
   "neg{l}\t%k0"
@@ -9369,16 +9366,11 @@
 (define_insn "*negsi2_cmpz_zext"
   [(set (reg:CCZ FLAGS_REG)
 	(compare:CCZ
-	  (lshiftrt:DI
-	    (neg:DI (ashift:DI
-		      (match_operand:DI 1 "register_operand" "0")
-		      (const_int 32)))
-	    (const_int 32))
+	  (neg:SI (match_operand:SI 1 "register_operand" "0"))
 	  (const_int 0)))
    (set (match_operand:DI 0 "register_operand" "=r")
-	(lshiftrt:DI (neg:DI (ashift:DI (match_dup 1)
-					(const_int 32)))
-		     (const_int 32)))]
+	(zero_extend:DI
+	  (neg:SI (match_dup 1))))]
   "TARGET_64BIT && ix86_unary_operator_ok (NEG, SImode, operands)"
   "neg{l}\t%k0"
   [(set_attr "type" "negnot")
@@ -9698,7 +9690,6 @@
   [(set_attr "type" "negnot")
    (set_attr "mode" "<MODE>")])
 
-;; ??? Currently never generated - xor is used instead.
 (define_insn "*one_cmplsi2_1_zext"
   [(set (match_operand:DI 0 "register_operand" "=r")
 	(zero_extend:DI
@@ -9749,7 +9740,6 @@
 	      (set (match_dup 1)
 		   (xor:SWI (match_dup 3) (const_int -1)))])])
 
-;; ??? Currently never generated - xor is used instead.
 (define_insn "*one_cmplsi2_2_zext"
   [(set (reg FLAGS_REG)
 	(compare (not:SI (match_operand:SI 1 "register_operand" "0"))
Index: testsuite/gcc.target/i386/pr91385.c
===================================================================
--- testsuite/gcc.target/i386/pr91385.c	(nonexistent)
+++ testsuite/gcc.target/i386/pr91385.c	(working copy)
@@ -0,0 +1,9 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O2 -dp" } */
+/* { dg-final { scan-assembler-not "zero_extendsidi" } } */
+
+unsigned long long
+foo (unsigned int a)
+{
+  return -a;
+}