The new test case in compiler/codegen/TestRedundantLea.java#Spill fails on MacOS because an additional decode is generated on that platform, which is currently not expected:

Scenario #0
===========
Scenario flags: [-XX:+IgnoreUnrecognizedVMOptions, -XX:-OptoPeephole]

One or more @IR rules failed:
1) Method "java.lang.String compiler.codegen.SpillTest.test()" - [Failed IR rules: 1]:
   * @IR rule 2: "@compiler.lib.ir_framework.IR(phase={FINAL_CODE}, applyIfPlatformAnd={}, applyIfCPUFeatureOr={}, counts={"_#DECODE_HEAP_OOP_NOT_NULL#_", "=2"}, applyIfPlatformOr={}, applyIfPlatform={}, failOn={}, applyIfOr={}, applyIfCPUFeatureAnd={}, applyIf={"OptoPeephole", "false"}, applyIfCPUFeature={}, applyIfAnd={}, applyIfNot={})"
     > Phase "Final Code":
       - counts: Graph contains wrong number of nodes:
         * Constraint 1: "decodeHeapOop_not_null"
           - Failed comparison: [found] 3 = 2 [given]
             - Matched nodes (3):
               * decodeHeapOop_not_null
               * decodeHeapOop_not_null
               * decodeHeapOop_not_null

Scenario #1
===========
Scenario flags: []

One or more @IR rules failed:
1) Method "java.lang.String compiler.codegen.SpillTest.test()" - [Failed IR rules: 1]:
   * @IR rule 3: "@compiler.lib.ir_framework.IR(phase={FINAL_CODE}, applyIfPlatformAnd={}, applyIfCPUFeatureOr={}, counts={}, applyIfPlatformOr={}, applyIfPlatform={}, failOn={"_#DECODE_HEAP_OOP_NOT_NULL#_"}, applyIfOr={}, applyIfCPUFeatureAnd={}, applyIf={"OptoPeephole", "true"}, applyIfCPUFeature={}, applyIfAnd={}, applyIfNot={})"
     > Phase "Final Code":
       - failOn: Graph contains forbidden nodes:
         * Constraint 1: "decodeHeapOop_not_null"
           - Matched forbidden node:
             * decodeHeapOop_not_null