Subzero: Refactor x86 register definitions to use the alias mechanism.

tests_lit/llvm2ice_tests/rng.ll

 ; This is a smoke test of random number generator.
 ; The random number generators for different randomization passes should be
 ; decoupled. The random number used in one randomization pass should not be
 ; influenced by the existence of other randomization passes.
 
 ; REQUIRES: allow_dump, target_X8632
 
 ; Command for checking constant blinding (Need to turn off nop-insertion)
 ; RUN: %p2i --target x8632 -i %s --filetype=obj --disassemble --args -O2 \
 ; RUN:    -sz-seed=1 -randomize-pool-immediates=randomize \
@@ skipping 171 matching lines @@
   %retval.0 = phi float [ %rbb, %sw.bb ], [ %rbb1, %sw.bb1 ], [ %rbb2, %sw.bb2 ], [ %rbb3, %sw.bb3 ], [ %rbb4, %sw.bb4], [ 0.000000e+00, %entry ]
   ret float %retval.0
 }
 
 define internal <4 x i32> @func4(<4 x i32> %a, <4 x i32> %b) {
 entry:
   %res = mul <4 x i32> %a, %b
   ret <4 x i32> %res
 
 ; REGALLOC-LABEL: func4
-; REGALLOC: movups  xmm3,xmm0
+; REGALLOC: movups  xmm5,xmm0
 ; REGALLOC-NEXT: pshufd  xmm0,xmm0,0x31
-; REGALLOC-NEXT: pshufd  xmm5,xmm1,0x31
-; REGALLOC-NEXT: pmuludq xmm3,xmm1
-; REGALLOC-NEXT: pmuludq xmm0,xmm5
-; REGALLOC-NEXT: shufps  xmm3,xmm0,0x88
-; REGALLOC-NEXT: pshufd  xmm3,xmm3,0xd8
-; REGALLOC-NEXT: movups  xmm0,xmm3
+; REGALLOC-NEXT: pshufd  xmm4,xmm1,0x31
+; REGALLOC-NEXT: pmuludq xmm5,xmm1
+; REGALLOC-NEXT: pmuludq xmm0,xmm4
+; REGALLOC-NEXT: shufps  xmm5,xmm0,0x88
+; REGALLOC-NEXT: pshufd  xmm5,xmm5,0xd8
+; REGALLOC-NEXT: movups  xmm0,xmm5
 ; REGALLOC-NEXT: ret
 }
 
 define internal void @func5(i32 %foo, i32 %bar) {
 entry:
   %r1 = icmp eq i32 %foo, %bar
   br i1 %r1, label %BB1, label %BB2
 BB1:
   %r2 = icmp sgt i32 %foo, %bar
   br i1 %r2, label %BB3, label %BB4
@@ skipping 39 matching lines @@
 ; GLOBALVARS-LABEL: ArrayUninit
 ; GLOBALVARS-LABEL: PrimitiveInitStatic
 ; GLOBALVARS-LABEL: ArrayUninitConstDouble
 ; GLOBALVARS-LABEL: ArrayUninitConstInt
 ; GLOBALVARS-LABEL: PrimitiveInitConst
 
 ; Check for pooled constant reordering
 ; POOLEDCONSTANTS-LABEL: .rodata.cst4
 ; POOLEDCONSTANTS: 0000803e 0000803f 00000000 0000003f
 ; POOLEDCONSTANTS: 00008040 00000040