Followup on Proposal to move MIR physical register namespace to '$' sigil.

Discussed here:

http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html

In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.

llvm-svn: 323922
diff --git a/llvm/test/CodeGen/Mips/compactbranches/empty-block.mir b/llvm/test/CodeGen/Mips/compactbranches/empty-block.mir
index 5bfaef0..83c489d 100644
--- a/llvm/test/CodeGen/Mips/compactbranches/empty-block.mir
+++ b/llvm/test/CodeGen/Mips/compactbranches/empty-block.mir
@@ -58,18 +58,18 @@
   hasVAStart:      false
   hasMustTailInVarArgFunc: false
 stack:
-  - { id: 0, type: spill-slot, offset: -4, size: 4, alignment: 4, callee-saved-register: '%ra' }
+  - { id: 0, type: spill-slot, offset: -4, size: 4, alignment: 4, callee-saved-register: '$ra' }
 body:             |
   bb.0.entry:
     successors: %bb.1.if.then(0x50000000), %bb.4.if.end(0x30000000)
-    liveins: %ra
+    liveins: $ra
 
-    %sp = ADDiu %sp, -24
+    $sp = ADDiu $sp, -24
     CFI_INSTRUCTION def_cfa_offset 24
-    SW killed %ra, %sp, 20 :: (store 4 into %stack.0)
-    CFI_INSTRUCTION offset %ra_64, -4
-    JAL @k, csr_o32_fp64, implicit-def dead %ra, implicit-def %sp, implicit-def %v0
-    BLEZ %v0, %bb.4.if.end, implicit-def %at
+    SW killed $ra, $sp, 20 :: (store 4 into %stack.0)
+    CFI_INSTRUCTION offset $ra_64, -4
+    JAL @k, csr_o32_fp64, implicit-def dead $ra, implicit-def $sp, implicit-def $v0
+    BLEZ $v0, %bb.4.if.end, implicit-def $at
 
   bb.1.if.then:
     successors: %bb.2.if.then(0x80000000)
@@ -80,12 +80,12 @@
   bb.3.if.then:
     successors: %bb.4.if.end(0x80000000)
 
-    %a0 = ADDiu %zero, 2
-    JAL @f, csr_o32_fp64, implicit-def dead %ra, implicit killed %a0, implicit-def %sp
+    $a0 = ADDiu $zero, 2
+    JAL @f, csr_o32_fp64, implicit-def dead $ra, implicit killed $a0, implicit-def $sp
 
   bb.4.if.end:
-    %ra = LW %sp, 20 :: (load 4 from %stack.0)
-    %sp = ADDiu %sp, 24
-    PseudoReturn undef %ra
+    $ra = LW $sp, 20 :: (load 4 from %stack.0)
+    $sp = ADDiu $sp, 24
+    PseudoReturn undef $ra
 
 ...