[gcc r14-4831] aarch64: Emit csinv again for `a ? ~b : b` [PR110986]

[gcc r14-4831] aarch64: Emit csinv again for `a ? ~b : b` [PR110986]

[Andrew Pinski]

https://gcc.gnu.org/g:bcc5054b36626459ddb04c779f0b201fba6001d1

commit r14-4831-gbcc5054b36626459ddb04c779f0b201fba6001d1
Author: Andrew Pinski <pinskia@gmail.com>
Date:   Wed Oct 18 16:39:12 2023 -0700

    aarch64: Emit csinv again for `a ? ~b : b` [PR110986]
    
    After r14-3110-g7fb65f10285, the canonical form for
    `a ? ~b : b` changed to be `-(a) ^ b` that means
    for aarch64 we need to add a few new insn patterns
    to be able to catch this and change it to be
    what is the canonical form for the aarch64 backend.
    A secondary pattern was needed to support a zero_extended
    form too; this adds a testcase for all 3 cases.
    
    Bootstrapped and tested on aarch64-linux-gnu with no regressions.
    
            PR target/110986
    
    gcc/ChangeLog:
    
            * config/aarch64/aarch64.md (*cmov<mode>_insn_insv): New pattern.
            (*cmov_uxtw_insn_insv): Likewise.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/cond_op-1.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64.md                | 47 ++++++++++++++++++++++++++++
 gcc/testsuite/gcc.target/aarch64/cond_op-1.c | 20 ++++++++++++
 2 files changed, 67 insertions(+)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index e6af09c2e8b3..5bb8c772be86 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -4413,6 +4413,53 @@
   [(set_attr "type" "csel")]
 )
 
+;; There are two canonical forms for `cmp ? ~a : a`.
+;; This is the second form and is here to help combine.
+;; Support `-(cmp) ^ a` into `cmp ? ~a : a`
+;; The second pattern is to support the zero extend'ed version.
+
+(define_insn_and_split "*cmov<mode>_insn_insv"
+  [(set (match_operand:GPI 0 "register_operand" "=r")
+        (xor:GPI
+	 (neg:GPI
+	  (match_operator:GPI 1 "aarch64_comparison_operator"
+	   [(match_operand 2 "cc_register" "") (const_int 0)]))
+	 (match_operand:GPI 3 "general_operand" "r")))]
+  ""
+  "#"
+  "&& true"
+  [(set (match_dup 0)
+	(if_then_else:GPI (match_dup 1)
+			  (not:GPI (match_dup 3))
+			  (match_dup 3)))]
+  {
+    /* After reload this will be a nop due to the constraint.  */
+    operands[3] = force_reg (<MODE>mode, operands[3]);
+  }
+  [(set_attr "type" "csel")]
+)
+
+(define_insn_and_split "*cmov_uxtw_insn_insv"
+  [(set (match_operand:DI 0 "register_operand" "=r")
+        (zero_extend:DI
+	 (xor:SI
+	  (neg:SI
+	   (match_operator:SI 1 "aarch64_comparison_operator"
+	    [(match_operand 2 "cc_register" "") (const_int 0)]))
+	  (match_operand:SI 3 "general_operand" "r"))))]
+  "can_create_pseudo_p ()"
+  "#"
+  "&& true"
+  [(set (match_dup 0)
+	(if_then_else:DI (match_dup 1)
+			  (zero_extend:DI (not:SI (match_dup 3)))
+			  (zero_extend:DI (match_dup 3))))]
+  {
+    operands[3] = force_reg (SImode, operands[3]);
+  }
+  [(set_attr "type" "csel")]
+)
+
 ;; If X can be loaded by a single CNT[BHWD] instruction,
 ;;
 ;;    A = UMAX (B, X)
diff --git a/gcc/testsuite/gcc.target/aarch64/cond_op-1.c b/gcc/testsuite/gcc.target/aarch64/cond_op-1.c
new file mode 100644
index 000000000000..e6c7821127e5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/cond_op-1.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* PR target/110986 */
+
+
+long long full(unsigned a, unsigned b)
+{
+  return a ? ~b : b;
+}
+unsigned fuu(unsigned a, unsigned b)
+{
+  return a ? ~b : b;
+}
+long long fllll(unsigned long long a, unsigned long long b)
+{
+  return a ? ~b : b;
+}
+
+/* { dg-final { scan-assembler-times "csinv\tw\[0-9\]*" 2 } } */
+/* { dg-final { scan-assembler-times "csinv\tx\[0-9\]*" 1 } } */