Subzero: Use "pxor reg,reg" to load a floating-point scalar 0.0 value.

tests_lit/llvm2ice_tests/reorder-pooled-constants.ll

 ; This is a smoke test for reordering pooled constants.
 ; This option is only implemented for target X8632 for now.
 
 ; RUN: %p2i --assemble --disassemble --filetype=obj --dis-flags=-s \
 ; RUN:   --target x8632 -i %s --args -sz-seed=1 -O2 -reorder-pooled-constants \
 ; RUN:   -allow-externally-defined-symbols | FileCheck %s --check-prefix=X86
 
 ; RUN: %p2i --assemble --disassemble --filetype=obj --dis-flags=-s \
 ; RUN:   --target x8632 -i %s --args -sz-seed=1 -Om1 -reorder-pooled-constants \
 ; RUN:   -allow-externally-defined-symbols | FileCheck %s --check-prefix=X86
@@ skipping 519 matching lines @@
 return:                                           ; preds = %entry, %sw.bb65, %sw.bb61, %sw.bb57, %sw.bb53, %sw.bb49, %sw.bb45, %sw.bb41, %sw.bb37, %sw.bb33, %sw.bb29, %sw.bb25, %sw.bb21, %sw.bb17, %sw.bb13, %sw.bb9, %sw.bb5, %sw.bb1, %sw.bb
   %retval.0 = phi double [ %add68, %sw.bb65 ], [ %add64, %sw.bb61 ], [ %add60, %sw.bb57 ], [ %add56, %sw.bb53 ], [ %add52, %sw.bb49 ], [ %conv48, %sw.bb45 ], [ %conv44, %sw.bb41 ], [ %conv40, %sw.bb37 ], [ %conv36, %sw.bb33 ], [ %add32, %sw.bb29 ], [ %add28, %sw.bb25 ], [ %add24, %sw.bb21 ], [ %add20, %sw.bb17 ], [ %add16, %sw.bb13 ], [ %conv12, %sw.bb9 ], [ %conv8, %sw.bb5 ], [ %conv4, %sw.bb1 ], [ %conv, %sw.bb ], [ 0.000000e+00, %entry ]
   ret double %retval.0
 }
 
 ; Make sure the constants in pools are shuffled.
 
 ; Check for float pool
 ; X86-LABEL: .rodata.cst4
 ; X86: 00000041 0000c0ff 0000803f 00008040
-; X86: 0000c07f 00000000 0000003f 0000803e
-; X86: 00000040
+; X86: 0000c07f 0000003f 0000803e 00000040
 
 ; Check for double pool
 ; X86-LABEL: .rodata.cst8
 ; X86: 00000000 0000f8ff 00000000 0000f87f
-; X86: 00000000 0000e03f 00000000 00000000
-; X86: 55555555 5555d53f 00000000 0000d03f
+; X86: 00000000 0000e03f 55555555 5555d53f
+; X86: 00000000 0000d03f
 
 ; X86-LABEL: .text