[SystemZ] Make more use of TMHH

This originally came about after noticing that InstCombine turns
some of the TMHH (icmp (and...), ...) tests into plain comparisons.
Since there is no instruction to compare with a 64-bit immediate,
TMHH is generally better than an ordered comparison for the cases
that it can handle.

llvm-svn: 197238

1 files changed, 109 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/SystemZ/int-cmp-47.ll b/llvm/test/CodeGen/SystemZ/int-cmp-47.ll
index 9ebcbfe525b..038a25b2a6e 100644
--- a/llvm/test/CodeGen/SystemZ/int-cmp-47.ll
+++ b/llvm/test/CodeGen/SystemZ/int-cmp-47.ll
@@ -232,3 +232,112 @@ store:
 exit:
   ret void
 }
+
+; Check a case where TMHH can be used to implement a ult comparison.
+define void @f13(i64 %a) {
+; CHECK-LABEL: f13:
+; CHECK: tmhh %r2, 49152
+; CHECK: jno {{\.L.*}}
+; CHECK: br %r14
+entry:
+  %cmp = icmp ult i64 %a, 13835058055282163712
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}
+
+; And again with ule.
+define void @f14(i64 %a) {
+; CHECK-LABEL: f14:
+; CHECK: tmhh %r2, 49152
+; CHECK: jno {{\.L.*}}
+; CHECK: br %r14
+entry:
+  %cmp = icmp ule i64 %a, 13835058055282163711
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}
+
+; And again with ugt.
+define void @f15(i64 %a) {
+; CHECK-LABEL: f15:
+; CHECK: tmhh %r2, 49152
+; CHECK: jo {{\.L.*}}
+; CHECK: br %r14
+entry:
+  %cmp = icmp ugt i64 %a, 13835058055282163711
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}
+
+; And again with uge.
+define void @f16(i64 %a) {
+; CHECK-LABEL: f16:
+; CHECK: tmhh %r2, 49152
+; CHECK: jo {{\.L.*}}
+; CHECK: br %r14
+entry:
+  %cmp = icmp uge i64 %a, 13835058055282163712
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}
+
+; Decrease the constant from f13 to make TMHH invalid.
+define void @f17(i64 %a) {
+; CHECK-LABEL: f17:
+; CHECK-NOT: tmhh
+; CHECK: llihh {{%r[0-5]}}, 49151
+; CHECK-NOT: tmhh
+; CHECK: br %r14
+entry:
+  %cmp = icmp ult i64 %a, 13834776580305453056
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}
+
+; Check that we don't use TMHH just to test the top bit.
+define void @f18(i64 %a) {
+; CHECK-LABEL: f18:
+; CHECK-NOT: tmhh
+; CHECK: cgijhe %r2, 0,
+; CHECK: br %r14
+entry:
+  %cmp = icmp ult i64 %a, 9223372036854775808
+  br i1 %cmp, label %exit, label %store
+
+store:
+  store i32 1, i32 *@g
+  br label %exit
+
+exit:
+  ret void
+}