Reid Spencer | 5d787bb | 2007-03-23 20:48:34 +0000 | [diff] [blame] | 1 | ; If we have an 'and' of the result of an 'or', and one of the 'or' operands |
| 2 | ; cannot have contributed any of the resultant bits, delete the or. This |
| 3 | ; occurs for very common C/C++ code like this: |
| 4 | ; |
| 5 | ; struct foo { int A : 16; int B : 16; }; |
| 6 | ; void test(struct foo *F, int X, int Y) { |
| 7 | ; F->A = X; F->B = Y; |
| 8 | ; } |
| 9 | ; |
| 10 | ; Which corresponds to test1. |
| 11 | ; |
| 12 | ; This tests arbitrary precision integers. |
| 13 | |
Chandler Carruth | 1de43ed | 2012-07-02 19:09:46 +0000 | [diff] [blame] | 14 | ; RUN: opt < %s -instcombine -S | not grep "or " |
Reid Spencer | 7c65d43 | 2007-04-15 07:38:21 +0000 | [diff] [blame] | 15 | ; END. |
Reid Spencer | 5d787bb | 2007-03-23 20:48:34 +0000 | [diff] [blame] | 16 | |
| 17 | define i17 @test1(i17 %X, i17 %Y) { |
| 18 | %A = and i17 %X, 7 |
| 19 | %B = and i17 %Y, 8 |
| 20 | %C = or i17 %A, %B |
| 21 | %D = and i17 %C, 7 ;; This cannot include any bits from %Y! |
| 22 | ret i17 %D |
| 23 | } |
| 24 | |
| 25 | define i49 @test3(i49 %X, i49 %Y) { |
| 26 | %B = shl i49 %Y, 1 |
| 27 | %C = or i49 %X, %B |
| 28 | %D = and i49 %C, 1 ;; This cannot include any bits from %Y! |
| 29 | ret i49 %D |
| 30 | } |
| 31 | |
| 32 | define i67 @test4(i67 %X, i67 %Y) { |
| 33 | %B = lshr i67 %Y, 66 |
| 34 | %C = or i67 %X, %B |
| 35 | %D = and i67 %C, 2 ;; This cannot include any bits from %Y! |
| 36 | ret i67 %D |
| 37 | } |
| 38 | |
| 39 | define i231 @or_test1(i231 %X, i231 %Y) { |
| 40 | %A = and i231 %X, 1 |
| 41 | %B = or i231 %A, 1 ;; This cannot include any bits from X! |
| 42 | ret i231 %B |
| 43 | } |
| 44 | |
| 45 | define i7 @or_test2(i7 %X, i7 %Y) { |
| 46 | %A = shl i7 %X, 6 |
| 47 | %B = or i7 %A, 64 ;; This cannot include any bits from X! |
| 48 | ret i7 %B |
| 49 | } |
| 50 | |