[NFC][PowerPC] Add a new MIR file to test if-converter pass

test/CodeGen/PowerPC/ifcvt.mir

@@ -0,0 +1,53 @@
+# RUN: llc -mtriple=ppc32-- -run-pass=if-converter -o - -verify-machineinstrs \
+# RUN:   %s | FileCheck %s
+
+---
+name:            testBDZLR
+body:             |
+  bb.0.entry:
+    successors: %bb.5(0x40000000), %bb.1(0x40000000)
+    liveins: $r3
+  
+    renamable $r4 = LI 0
+    renamable $cr0 = CMPLWI killed renamable $r4, 0
+    BCC 68, renamable $cr0, %bb.5
+  
+  bb.1:
+    successors: %bb.2(0x40000000), %bb.5(0x40000000)
+    liveins: $cr0, $r3
+  
+    BCC 68, killed renamable $cr0, %bb.5
+  
+  bb.2:
+    successors: %bb.3(0x80000000)
+    liveins: $r3
+  
+    MTCTRloop killed renamable $r3, implicit-def dead $ctr
+    renamable $r3 = LI 0
+    renamable $r5 = IMPLICIT_DEF
+    renamable $r4 = LI 0
+  
+  bb.3:
+    successors: %bb.4(0x7c000000), %bb.5(0x04000000)
+    liveins: $r3, $r4, $r5
+  
+    renamable $r6 = RLWINM renamable $r4, 3, 0, 28
+    renamable $r4 = ADDIC killed renamable $r4, 1, implicit-def $carry
+    renamable $r5 = ADD4 killed renamable $r5, killed renamable $r6
+    renamable $r6 = ADD4 killed renamable $r6, renamable $r6
+    renamable $r3 = ADDZE killed renamable $r3, implicit-def dead $carry, implicit $carry
+    BDZ %bb.5, implicit-def $ctr, implicit $ctr
+  
+  bb.4:
+    successors: %bb.3(0x80000000)
+    liveins: $r3, $r4
+  
+    B %bb.3
+  
+  bb.5:
+    BLR implicit $lr, implicit $rm
+
+
+  ; CHECK-LABEL: name: testBDZLR
+  ; CHECK: BDZLR implicit $lr, implicit $rm
+...