; 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 | |
} | |