[SystemZ] Add CodeGen test cases

This adds all CodeGen tests for the SystemZ target.

This version of the patch incorporates feedback from a review by
Sean Silva.  Thanks to all reviewers!

Patch by Richard Sandiford.

llvm-svn: 181204
diff --git a/llvm/test/CodeGen/SystemZ/int-conv-07.ll b/llvm/test/CodeGen/SystemZ/int-conv-07.ll
new file mode 100644
index 0000000..041caa2
--- /dev/null
+++ b/llvm/test/CodeGen/SystemZ/int-conv-07.ll
@@ -0,0 +1,105 @@
+; Test sign extensions from a halfword to an i64.
+;
+; RUN: llc < %s -mtriple=s390x-linux-gnu | FileCheck %s
+
+; Test register extension, starting with an i32.
+define i64 @f1(i64 %a) {
+; CHECK: f1:
+; CHECK: lghr %r2, %r2
+; CHECk: br %r14
+  %half = trunc i64 %a to i16
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; ...and again with an i64.
+define i64 @f2(i32 %a) {
+; CHECK: f2:
+; CHECK: lghr %r2, %r2
+; CHECk: br %r14
+  %half = trunc i32 %a to i16
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check LGH with no displacement.
+define i64 @f3(i16 *%src) {
+; CHECK: f3:
+; CHECK: lgh %r2, 0(%r2)
+; CHECK: br %r14
+  %half = load i16 *%src
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check the high end of the LGH range.
+define i64 @f4(i16 *%src) {
+; CHECK: f4:
+; CHECK: lgh %r2, 524286(%r2)
+; CHECK: br %r14
+  %ptr = getelementptr i16 *%src, i64 262143
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check the next halfword up, which needs separate address logic.
+; Other sequences besides this one would be OK.
+define i64 @f5(i16 *%src) {
+; CHECK: f5:
+; CHECK: agfi %r2, 524288
+; CHECK: lgh %r2, 0(%r2)
+; CHECK: br %r14
+  %ptr = getelementptr i16 *%src, i64 262144
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check the high end of the negative LGH range.
+define i64 @f6(i16 *%src) {
+; CHECK: f6:
+; CHECK: lgh %r2, -2(%r2)
+; CHECK: br %r14
+  %ptr = getelementptr i16 *%src, i64 -1
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check the low end of the LGH range.
+define i64 @f7(i16 *%src) {
+; CHECK: f7:
+; CHECK: lgh %r2, -524288(%r2)
+; CHECK: br %r14
+  %ptr = getelementptr i16 *%src, i64 -262144
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check the next halfword down, which needs separate address logic.
+; Other sequences besides this one would be OK.
+define i64 @f8(i16 *%src) {
+; CHECK: f8:
+; CHECK: agfi %r2, -524290
+; CHECK: lgh %r2, 0(%r2)
+; CHECK: br %r14
+  %ptr = getelementptr i16 *%src, i64 -262145
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}
+
+; Check that LGH allows an index.
+define i64 @f9(i64 %src, i64 %index) {
+; CHECK: f9:
+; CHECK: lgh %r2, 524287(%r3,%r2)
+; CHECK: br %r14
+  %add1 = add i64 %src, %index
+  %add2 = add i64 %add1, 524287
+  %ptr = inttoptr i64 %add2 to i16 *
+  %half = load i16 *%ptr
+  %ext = sext i16 %half to i64
+  ret i64 %ext
+}