[PowerPC] Precommit test to show impact of early-ifcvt on target without isel. NFC.

Author: Kai Luo

llvm/test/CodeGen/PowerPC/early-ifcvt-no-isel.mir

@@ -0,0 +1,73 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 4
+# RUN: llc -mtriple=powerpc64-ibm-aix -mcpu=pwr7 -simplify-mir -verify-machineinstrs \
+# RUN:   -run-pass=early-ifcvt %s -o - | FileCheck %s
+
+--- |
+  source_filename = "<stdin>"
+
+  define signext i32 @foo(ptr nocapture noundef %dummy) #0 {
+  entry:
+    %0 = load i32, ptr %dummy, align 4
+    %cmp = icmp slt i32 %0, 750
+    %inc = add nsw i32 %0, 1
+    %storemerge = select i1 %cmp, i32 %inc, i32 1
+    store i32 %storemerge, ptr %dummy, align 4
+    ret i32 0
+  }
+
+  attributes #0 = { "target-features"="-isel" }
+
+...
+---
+name:            foo
+alignment:       16
+tracksRegLiveness: true
+registers:
+  - { id: 0, class: g8rc_and_g8rc_nox0 }
+  - { id: 1, class: gprc_and_gprc_nor0 }
+  - { id: 2, class: gprc_and_gprc_nor0 }
+  - { id: 3, class: crrc }
+  - { id: 4, class: gprc_and_gprc_nor0 }
+  - { id: 5, class: gprc }
+  - { id: 6, class: g8rc }
+liveins:
+  - { reg: '$x3', virtual-reg: '%0' }
+frameInfo:
+  maxAlignment:    1
+machineFunctionInfo: {}
+body:             |
+  ; CHECK-LABEL: name: foo
+  ; CHECK: bb.0.entry:
+  ; CHECK-NEXT:   liveins: $x3
+  ; CHECK-NEXT: {{  $}}
+  ; CHECK-NEXT:   [[COPY:%[0-9]+]]:g8rc_and_g8rc_nox0 = COPY $x3
+  ; CHECK-NEXT:   [[LWZ:%[0-9]+]]:gprc_and_gprc_nor0 = LWZ 0, [[COPY]] :: (load (s32) from %ir.dummy)
+  ; CHECK-NEXT:   [[ADDI:%[0-9]+]]:gprc_and_gprc_nor0 = nsw ADDI [[LWZ]], 1
+  ; CHECK-NEXT:   [[CMPWI:%[0-9]+]]:crrc = CMPWI [[LWZ]], 750
+  ; CHECK-NEXT:   [[LI:%[0-9]+]]:gprc_and_gprc_nor0 = LI 1
+  ; CHECK-NEXT:   [[ISEL:%[0-9]+]]:gprc = ISEL [[ADDI]], [[LI]], [[CMPWI]].sub_lt
+  ; CHECK-NEXT:   STW killed [[ISEL]], 0, [[COPY]] :: (store (s32) into %ir.dummy)
+  ; CHECK-NEXT:   [[LI8_:%[0-9]+]]:g8rc = LI8 0
+  ; CHECK-NEXT:   $x3 = COPY [[LI8_]]
+  ; CHECK-NEXT:   BLR8 implicit $lr8, implicit $rm, implicit $x3
+  bb.0.entry:
+    successors: %bb.1, %bb.2
+    liveins: $x3
+
+    %0:g8rc_and_g8rc_nox0 = COPY $x3
+    %1:gprc_and_gprc_nor0 = LWZ 0, %0 :: (load (s32) from %ir.dummy)
+    %2:gprc_and_gprc_nor0 = nsw ADDI %1, 1
+    %3:crrc = CMPWI %1, 750
+    %4:gprc_and_gprc_nor0 = LI 1
+    BCC 12, %3, %bb.2
+
+  bb.1.entry:
+
+  bb.2.entry:
+    %5:gprc = PHI %4, %bb.1, %2, %bb.0
+    STW killed %5, 0, %0 :: (store (s32) into %ir.dummy)
+    %6:g8rc = LI8 0
+    $x3 = COPY %6
+    BLR8 implicit $lr8, implicit $rm, implicit $x3
+
+...