; RUN: llc < %s -march=x86 | FileCheck %s
define i32 @t1(i8* %X, i32 %i) {
-; CHECK: t1:
+; CHECK-LABEL: t1:
; CHECK-NOT: and
; CHECK: movzbl
; CHECK: movl (%{{...}},%{{...}},4),
}
define i32 @t2(i16* %X, i32 %i) {
-; CHECK: t2:
+; CHECK-LABEL: t2:
; CHECK-NOT: and
; CHECK: movzwl
; CHECK: movl (%{{...}},%{{...}},4),
%tmp9 = load i32* %tmp78
ret i32 %tmp9
}
+
+define i32 @t3(i16* %i.ptr, i32* %arr) {
+; This case is tricky. The lshr followed by a gep will produce a lshr followed
+; by an and to remove the low bits. This can be simplified by doing the lshr by
+; a greater constant and using the addressing mode to scale the result back up.
+; To make matters worse, because of the two-phase zext of %i and their reuse in
+; the function, the DAG can get confusing trying to re-use both of them and
+; prevent easy analysis of the mask in order to match this.
+; CHECK-LABEL: t3:
+; CHECK-NOT: and
+; CHECK: shrl
+; CHECK: addl (%{{...}},%{{...}},4),
+; CHECK: ret
+
+entry:
+ %i = load i16* %i.ptr
+ %i.zext = zext i16 %i to i32
+ %index = lshr i32 %i.zext, 11
+ %val.ptr = getelementptr inbounds i32* %arr, i32 %index
+ %val = load i32* %val.ptr
+ %sum = add i32 %val, %i.zext
+ ret i32 %sum
+}
+
+define i32 @t4(i16* %i.ptr, i32* %arr) {
+; A version of @t3 that has more zero extends and more re-use of intermediate
+; values. This exercise slightly different bits of canonicalization.
+; CHECK-LABEL: t4:
+; CHECK-NOT: and
+; CHECK: shrl
+; CHECK: addl (%{{...}},%{{...}},4),
+; CHECK: ret
+
+entry:
+ %i = load i16* %i.ptr
+ %i.zext = zext i16 %i to i32
+ %index = lshr i32 %i.zext, 11
+ %index.zext = zext i32 %index to i64
+ %val.ptr = getelementptr inbounds i32* %arr, i64 %index.zext
+ %val = load i32* %val.ptr
+ %sum.1 = add i32 %val, %i.zext
+ %sum.2 = add i32 %sum.1, %index
+ ret i32 %sum.2
+}