[PATCHv2, rs6000] Enable have_cbranchcc4 on rs6000

[HAO CHEN GUI <guihaoc@linux.ibm.com>]

Hi,
  The patch enables have_cbrnachcc4 which is a flag in ifcvt.cc to
indicate if branch by CC bits is invalid or not. The new expand pattern
"cbranchcc4" is created which intend to match the pattern defined in
"*cbranch", "*cbranch_2insn" and "*creturn". The operand sequence in
"cbranchcc4" is inline with the definition in gccint. And the operand
sequence doesn't matter in pattern matching. So I think it should work.

  Compared to last version, one new predicate and one new expander are
created.

  Bootstrapped and tested on powerpc64-linux BE and LE with no regressions.
Is this okay for trunk? Any recommendations? Thanks a lot.

ChangeLog
2022-11-17  Haochen Gui <guihaoc@linux.ibm.com>

gcc/
	* config/rs6000/predicates.md (all_branch_comparison_operator): New,
	and includes operators in branch_comparison_operator and
	extra_insn_branch_comparison_operator.
	* config/rs6000/rs6000.md (cbranchcc4): New expand pattern.

gcc/testsuite/
	* gcc.target/powerpc/cbranchcc4.c: New.


patch.diff
diff --git a/gcc/config/rs6000/predicates.md b/gcc/config/rs6000/predicates.md
index b1fcc69bb60..843b6f39b84 100644
--- a/gcc/config/rs6000/predicates.md
+++ b/gcc/config/rs6000/predicates.md
@@ -1308,6 +1308,7 @@ (define_special_predicate "equality_operator"

 ;; Return 1 if OP is a comparison operation that is valid for a branch
 ;; instruction.  We check the opcode against the mode of the CC value.
+
 ;; validate_condition_mode is an assertion.
 (define_predicate "branch_comparison_operator"
    (and (match_operand 0 "comparison_operator")
@@ -1331,6 +1332,11 @@ (define_predicate "extra_insn_branch_comparison_operator"
 					      GET_MODE (XEXP (op, 0))),
 		     1")))

+;; Return 1 if OP is a comparison operation that is valid for a branch.
+(define_predicate "all_branch_comparison_operator"
+   (ior (match_operand 0 "branch_comparison_operator")
+	(match_operand 0 "extra_insn_branch_comparison_operator")))
+
 ;; Return 1 if OP is an unsigned comparison operator.
 (define_predicate "unsigned_comparison_operator"
   (match_code "ltu,gtu,leu,geu"))
diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
index e9e5cd1e54d..7b7d747a85d 100644
--- a/gcc/config/rs6000/rs6000.md
+++ b/gcc/config/rs6000/rs6000.md
@@ -13067,6 +13067,16 @@ (define_insn_and_split "*<code><mode>_cc"
 ;; Conditional branches.
 ;; These either are a single bc insn, or a bc around a b.

+(define_expand "cbranchcc4"
+  [(set (pc)
+	(if_then_else (match_operator 0 "all_branch_comparison_operator"
+			[(match_operand 1 "cc_reg_operand")
+			 (match_operand 2 "zero_constant")])
+		      (label_ref (match_operand 3))
+		      (pc)))]
+  ""
+  "")
+
 (define_insn "*cbranch"
   [(set (pc)
 	(if_then_else (match_operator 1 "branch_comparison_operator"
diff --git a/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c b/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c
new file mode 100644
index 00000000000..528ba1a878d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/cbranchcc4.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-rtl-ce1" } */
+/* { dg-final { scan-rtl-dump "noce_try_store_flag_constants" "ce1" } } */
+
+/* The inner branch should be detected by ifcvt then be converted to a setcc
+   with a plus by noce_try_store_flag_constants.  */
+
+int test (unsigned int a, unsigned int b)
+{
+    return (a < b ? 0 : (a > b ? 2 : 1));
+}