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| ; If we have an 'and' of the result of an 'or', and one of the 'or' operands
| ; cannot have contributed any of the resultant bits, delete the or. This
| ; occurs for very common C/C++ code like this:
| ;
| ; struct foo { int A : 16; int B : 16; };
| ; void test(struct foo *F, int X, int Y) {
| ; F->A = X; F->B = Y;
| ; }
| ;
| ; Which corresponds to test1.
| ;
| ; This tests arbitrary precision integers.
|
| ; RUN: opt < %s -instcombine -S | not grep "or "
| ; END.
|
| define i17 @test1(i17 %X, i17 %Y) {
| %A = and i17 %X, 7
| %B = and i17 %Y, 8
| %C = or i17 %A, %B
| %D = and i17 %C, 7 ;; This cannot include any bits from %Y!
| ret i17 %D
| }
|
| define i49 @test3(i49 %X, i49 %Y) {
| %B = shl i49 %Y, 1
| %C = or i49 %X, %B
| %D = and i49 %C, 1 ;; This cannot include any bits from %Y!
| ret i49 %D
| }
|
| define i67 @test4(i67 %X, i67 %Y) {
| %B = lshr i67 %Y, 66
| %C = or i67 %X, %B
| %D = and i67 %C, 2 ;; This cannot include any bits from %Y!
| ret i67 %D
| }
|
| define i231 @or_test1(i231 %X, i231 %Y) {
| %A = and i231 %X, 1
| %B = or i231 %A, 1 ;; This cannot include any bits from X!
| ret i231 %B
| }
|
| define i7 @or_test2(i7 %X, i7 %Y) {
| %A = shl i7 %X, 6
| %B = or i7 %A, 64 ;; This cannot include any bits from X!
| ret i7 %B
| }
|
|
