Chris Lattner | 584e383 | 2005-01-01 16:14:18 +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 | |
Reid Spencer | 91948d4 | 2007-04-14 20:13:02 +0000 | [diff] [blame] | 12 | ; RUN: llvm-upgrade < %s | llvm-as | opt -instcombine | llvm-dis | \ |
| 13 | ; RUN: not grep {or } |
Reid Spencer | ede8c3b | 2007-04-15 07:38:21 +0000 | [diff] [blame^] | 14 | ; END. |
Chris Lattner | 584e383 | 2005-01-01 16:14:18 +0000 | [diff] [blame] | 15 | |
| 16 | int %test1(int %X, int %Y) { |
| 17 | %A = and int %X, 7 |
| 18 | %B = and int %Y, 8 |
| 19 | %C = or int %A, %B |
| 20 | %D = and int %C, 7 ;; This cannot include any bits from %Y! |
| 21 | ret int %D |
| 22 | } |
| 23 | |
| 24 | int %test2(int %X, ubyte %Y) { |
| 25 | %B = cast ubyte %Y to int |
| 26 | %C = or int %X, %B |
| 27 | %D = and int %C, 65536 ;; This cannot include any bits from %Y! |
| 28 | ret int %D |
| 29 | } |
| 30 | |
| 31 | int %test3(int %X, int %Y) { |
| 32 | %B = shl int %Y, ubyte 1 |
| 33 | %C = or int %X, %B |
| 34 | %D = and int %C, 1 ;; This cannot include any bits from %Y! |
| 35 | ret int %D |
| 36 | } |
| 37 | |
| 38 | uint %test4(uint %X, uint %Y) { |
| 39 | %B = shr uint %Y, ubyte 31 |
| 40 | %C = or uint %X, %B |
| 41 | %D = and uint %C, 2 ;; This cannot include any bits from %Y! |
| 42 | ret uint %D |
| 43 | } |
| 44 | |
| 45 | int %or_test1(int %X, int %Y) { |
| 46 | %A = and int %X, 1 |
| 47 | %B = or int %A, 1 ;; This cannot include any bits from X! |
| 48 | ret int %B |
| 49 | } |
| 50 | |
| 51 | ubyte %or_test2(ubyte %X, ubyte %Y) { |
| 52 | %A = shl ubyte %X, ubyte 7 |
| 53 | %B = or ubyte %A, 128 ;; This cannot include any bits from X! |
| 54 | ret ubyte %B |
| 55 | } |
| 56 | |