1 files changed, 69 insertions, 13 deletions
diff --git a/test/CodeGen/X86/fold-and-shift.ll b/test/CodeGen/X86/fold-and-shift.ll
index 9f79f7723b33..93baa0e0eee0 100644
--- a/test/CodeGen/X86/fold-and-shift.ll
+++ b/test/CodeGen/X86/fold-and-shift.ll
@@ -1,21 +1,77 @@
-; RUN: llc < %s -march=x86 | not grep and
+; RUN: llc < %s -march=x86 | FileCheck %s
 
 define i32 @t1(i8* %X, i32 %i) {
+; CHECK: t1:
+; CHECK-NOT: and
+; CHECK: movzbl
+; CHECK: movl (%{{...}},%{{...}},4),
+; CHECK: ret
+
 entry:
-	%tmp2 = shl i32 %i, 2		; <i32> [#uses=1]
-	%tmp4 = and i32 %tmp2, 1020		; <i32> [#uses=1]
-	%tmp7 = getelementptr i8* %X, i32 %tmp4		; <i8*> [#uses=1]
-	%tmp78 = bitcast i8* %tmp7 to i32*		; <i32*> [#uses=1]
-	%tmp9 = load i32* %tmp78, align 4		; <i32> [#uses=1]
-	ret i32 %tmp9
+  %tmp2 = shl i32 %i, 2
+  %tmp4 = and i32 %tmp2, 1020
+  %tmp7 = getelementptr i8* %X, i32 %tmp4
+  %tmp78 = bitcast i8* %tmp7 to i32*
+  %tmp9 = load i32* %tmp78
+  ret i32 %tmp9
 }
 
 define i32 @t2(i16* %X, i32 %i) {
+; CHECK: t2:
+; CHECK-NOT: and
+; CHECK: movzwl
+; CHECK: movl (%{{...}},%{{...}},4),
+; CHECK: ret
+
+entry:
+  %tmp2 = shl i32 %i, 1
+  %tmp4 = and i32 %tmp2, 131070
+  %tmp7 = getelementptr i16* %X, i32 %tmp4
+  %tmp78 = bitcast i16* %tmp7 to i32*
+  %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: 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: t4:
+; CHECK-NOT: and
+; CHECK: shrl
+; CHECK: addl (%{{...}},%{{...}},4),
+; CHECK: ret
+
 entry:
-	%tmp2 = shl i32 %i, 1		; <i32> [#uses=1]
-	%tmp4 = and i32 %tmp2, 131070		; <i32> [#uses=1]
-	%tmp7 = getelementptr i16* %X, i32 %tmp4		; <i16*> [#uses=1]
-	%tmp78 = bitcast i16* %tmp7 to i32*		; <i32*> [#uses=1]
-	%tmp9 = load i32* %tmp78, align 4		; <i32> [#uses=1]
-	ret i32 %tmp9
+  %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
 }