p := e.b
				if end[p.ID] != flag {
					f.Fatalf("live flag in %s's predecessors not consistent", b)
				}
			}
		}
		for _, v := range oldSched {
			if v.Op == OpPhi && v.Type.IsFlags() {
				f.Fatalf("phi of flags not supported: %s", v.LongString())
			}

			// If v will be spilled, and v uses memory, then we must split it
			// into a load + a flag generator.
			if spill[v.ID] && v.MemoryArg() != nil {

00000220  8d 65 5e 6d ea 9e c3 95  f4 1b 15 bb 91 ac 9c 0b  |.e^m............|
00000230  13 f0 fa ab 46 ed f1 c5  29 6e 45 db 4c cc 1e 45  |....F...)nE.L..E|
00000240  4d fc f2 6c 2b 0a d0 f3  70 69 32 cd 2f 23 6d f2  |M..l+...pi2./#m.|
00000250  5f f3 f4 f0 5c 1c d7 d3  a7 0c 8f 23 29 30 7a 8e  |_...\......#)0z.|
00000260  c3 aa a8 71 21 5c ad b6  fb c6 bd 78 ac ab b1 a0  |...q!\.....x....|

//
//	   b        b           b       b
//	\ / \ /    | \  /    \ / |     | |
//	 s0  s1    |  s1      s0 |     | |
//	  \ /      | /         \ |     | |
//	   ss      ss           ss      ss
//
// If all Phi ops in ss have identical variables for slots corresponding to
// s0, s1 and b then the branch can be dropped.
// This optimization often comes up in switch statements with multiple
// expressions in a case clause:
//

// partitionValues partitions the values into equivalence classes
// based on having all the following features match:
//   - opcode
//   - type
//   - auxint
//   - aux
//   - nargs
//   - block # if a phi op
//   - first two arg's opcodes and auxint
//   - NOT first two arg's aux; that can break CSE.
//
// partitionValues returns a list of equivalence classes, each