cmd/compile: add additional flag constant folding rules

Fixes #73200

Change-Id: I77518d37acd838acf79ed113194bac5e2c30897f
Reviewed-on: https://go-review.googlesource.com/c/go/+/663535
Reviewed-by: David Chase <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Keith Randall <[email protected]>
Reviewed-by: Cuong Manh Le <[email protected]>

Author: randall77

src/cmd/compile/internal/ssa/_gen/ARM64.rules

@@ -1385,16 +1385,18 @@
 (CSNEG [cc] x y (InvertFlags cmp)) => (CSNEG [arm64Invert(cc)] x y cmp)
 
 // absorb flag constants into boolean values
-(Equal         (FlagConstant [fc])) => (MOVDconst [b2i(fc.eq())])
-(NotEqual      (FlagConstant [fc])) => (MOVDconst [b2i(fc.ne())])
-(LessThan      (FlagConstant [fc])) => (MOVDconst [b2i(fc.lt())])
-(LessThanU     (FlagConstant [fc])) => (MOVDconst [b2i(fc.ult())])
-(LessEqual     (FlagConstant [fc])) => (MOVDconst [b2i(fc.le())])
-(LessEqualU    (FlagConstant [fc])) => (MOVDconst [b2i(fc.ule())])
-(GreaterThan   (FlagConstant [fc])) => (MOVDconst [b2i(fc.gt())])
-(GreaterThanU  (FlagConstant [fc])) => (MOVDconst [b2i(fc.ugt())])
-(GreaterEqual  (FlagConstant [fc])) => (MOVDconst [b2i(fc.ge())])
-(GreaterEqualU (FlagConstant [fc])) => (MOVDconst [b2i(fc.uge())])
+(Equal             (FlagConstant [fc])) => (MOVDconst [b2i(fc.eq())])
+(NotEqual          (FlagConstant [fc])) => (MOVDconst [b2i(fc.ne())])
+(LessThan          (FlagConstant [fc])) => (MOVDconst [b2i(fc.lt())])
+(LessThanU         (FlagConstant [fc])) => (MOVDconst [b2i(fc.ult())])
+(LessEqual         (FlagConstant [fc])) => (MOVDconst [b2i(fc.le())])
+(LessEqualU        (FlagConstant [fc])) => (MOVDconst [b2i(fc.ule())])
+(GreaterThan       (FlagConstant [fc])) => (MOVDconst [b2i(fc.gt())])
+(GreaterThanU      (FlagConstant [fc])) => (MOVDconst [b2i(fc.ugt())])
+(GreaterEqual      (FlagConstant [fc])) => (MOVDconst [b2i(fc.ge())])
+(GreaterEqualU     (FlagConstant [fc])) => (MOVDconst [b2i(fc.uge())])
+(LessThanNoov      (FlagConstant [fc])) => (MOVDconst [b2i(fc.ltNoov())])
+(GreaterEqualNoov  (FlagConstant [fc])) => (MOVDconst [b2i(fc.geNoov())])
 
 // absorb InvertFlags into boolean values
 (Equal            (InvertFlags x)) => (Equal x)

src/cmd/compile/internal/ssa/rewriteARM64.go

@@ -0,0 +1,36 @@
+// build
+
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package main
+
+var g bool
+
+func main() {
+	l_4 := uint32(0x6E54EE87)
+	v4 := int8(-Int64FromInt64(1))
+	g = int32(v4) >= safe_mod_func_int32_t_s_s(BoolInt32(l_4 >= 1), 7)
+}
+
+func safe_mod_func_int32_t_s_s(si1 int32, si2 int32) (r int32) {
+	var v1 int32
+	if si2 == 0 {
+		v1 = si1
+	} else {
+		v1 = si1 % si2
+	}
+	return v1
+}
+
+func Int64FromInt64(n int64) int64 {
+	return n
+}
+
+func BoolInt32(b bool) int32 {
+	if b {
+		return 1
+	}
+	return 0
+}