[PowerPC] Add test case for missing nsw flag. NFC.

Author: Kai Luo

llvm/test/CodeGen/PowerPC/setcc-sub-flag.ll

@@ -0,0 +1,33 @@
+; RUN: llc -mtriple=powerpc64le -simplify-mir -verify-machineinstrs \
+; RUN:   -stop-after=finalize-isel < %s | FileCheck %s
+
+declare void @foo(i64)
+declare void @bar(i1)
+
+define void @f(i64 %a, i64 %b) {
+  ; CHECK-LABEL: name: f
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK:   liveins: $x3, $x4
+  ; CHECK:   [[COPY:%[0-9]+]]:g8rc = COPY $x4
+  ; CHECK:   [[COPY1:%[0-9]+]]:g8rc = COPY $x3
+  ; CHECK:   [[SUBF8_:%[0-9]+]]:g8rc = SUBF8 [[COPY1]], [[COPY]]
+  %c = sub nsw i64 %b, %a
+  call void @foo(i64 %c)
+  %d = icmp slt i64 %a, %b
+  call void @bar(i1 %d)
+  ret void
+}
+
+define void @g(i64 %a, i64 %b) {
+  ; CHECK-LABEL: name: g
+  ; CHECK: bb.0 (%ir-block.0):
+  ; CHECK:   liveins: $x3, $x4
+  ; CHECK:   [[COPY:%[0-9]+]]:g8rc = COPY $x4
+  ; CHECK:   [[COPY1:%[0-9]+]]:g8rc = COPY $x3
+  ; CHECK:   [[SUBF8_:%[0-9]+]]:g8rc = nsw SUBF8 [[COPY]], [[COPY1]]
+  %c = sub nsw i64 %a, %b
+  call void @foo(i64 %c)
+  %d = icmp slt i64 %a, %b
+  call void @bar(i1 %d)
+  ret void
+}