| Dan Gohman | 72a13d2 | 2009-09-08 22:34:10 +0000 | [diff] [blame] | 1 | ; RUN: opt < %s -instcombine -S > %t |
| Dan Gohman | bf0002e | 2009-05-21 02:28:33 +0000 | [diff] [blame] | 2 | ; RUN: not grep lshr %t |
| 3 | ; RUN: grep add %t | count 1 |
| 4 | |
| 5 | ; Instcombine should be able to eliminate the lshr, because only |
| 6 | ; bits in the operand which might be non-zero will be shifted |
| 7 | ; off the end. |
| 8 | |
| 9 | define i32 @hash_string(i8* nocapture %key) nounwind readonly { |
| 10 | entry: |
| 11 | %t0 = load i8* %key, align 1 ; <i8> [#uses=1] |
| 12 | %t1 = icmp eq i8 %t0, 0 ; <i1> [#uses=1] |
| 13 | br i1 %t1, label %bb2, label %bb |
| 14 | |
| 15 | bb: ; preds = %bb, %entry |
| 16 | %indvar = phi i64 [ 0, %entry ], [ %tmp, %bb ] ; <i64> [#uses=2] |
| 17 | %k.04 = phi i32 [ 0, %entry ], [ %t8, %bb ] ; <i32> [#uses=2] |
| 18 | %cp.05 = getelementptr i8* %key, i64 %indvar ; <i8*> [#uses=1] |
| 19 | %t2 = shl i32 %k.04, 1 ; <i32> [#uses=1] |
| 20 | %t3 = lshr i32 %k.04, 14 ; <i32> [#uses=1] |
| 21 | %t4 = add i32 %t2, %t3 ; <i32> [#uses=1] |
| 22 | %t5 = load i8* %cp.05, align 1 ; <i8> [#uses=1] |
| 23 | %t6 = sext i8 %t5 to i32 ; <i32> [#uses=1] |
| 24 | %t7 = xor i32 %t6, %t4 ; <i32> [#uses=1] |
| 25 | %t8 = and i32 %t7, 16383 ; <i32> [#uses=2] |
| 26 | %tmp = add i64 %indvar, 1 ; <i64> [#uses=2] |
| 27 | %scevgep = getelementptr i8* %key, i64 %tmp ; <i8*> [#uses=1] |
| 28 | %t9 = load i8* %scevgep, align 1 ; <i8> [#uses=1] |
| 29 | %t10 = icmp eq i8 %t9, 0 ; <i1> [#uses=1] |
| 30 | br i1 %t10, label %bb2, label %bb |
| 31 | |
| 32 | bb2: ; preds = %bb, %entry |
| 33 | %k.0.lcssa = phi i32 [ 0, %entry ], [ %t8, %bb ] ; <i32> [#uses=1] |
| 34 | ret i32 %k.0.lcssa |
| 35 | } |