llvm/test/Transforms/InstCombine/and-or-and.ll
Dan Gohman f2f6ce65b7 Change tests from "opt %s" to "opt < %s" so that opt doesn't see the
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81537 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-11 18:01:28 +00:00

62 lines
2.0 KiB
LLVM

; 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.
; RUN: opt < %s -instcombine -S | \
; RUN: not grep {or }
define i32 @test1(i32 %X, i32 %Y) {
%A = and i32 %X, 7 ; <i32> [#uses=1]
%B = and i32 %Y, 8 ; <i32> [#uses=1]
%C = or i32 %A, %B ; <i32> [#uses=1]
;; This cannot include any bits from %Y!
%D = and i32 %C, 7 ; <i32> [#uses=1]
ret i32 %D
}
define i32 @test2(i32 %X, i8 %Y) {
%B = zext i8 %Y to i32 ; <i32> [#uses=1]
%C = or i32 %X, %B ; <i32> [#uses=1]
;; This cannot include any bits from %Y!
%D = and i32 %C, 65536 ; <i32> [#uses=1]
ret i32 %D
}
define i32 @test3(i32 %X, i32 %Y) {
%B = shl i32 %Y, 1 ; <i32> [#uses=1]
%C = or i32 %X, %B ; <i32> [#uses=1]
;; This cannot include any bits from %Y!
%D = and i32 %C, 1 ; <i32> [#uses=1]
ret i32 %D
}
define i32 @test4(i32 %X, i32 %Y) {
%B = lshr i32 %Y, 31 ; <i32> [#uses=1]
%C = or i32 %X, %B ; <i32> [#uses=1]
;; This cannot include any bits from %Y!
%D = and i32 %C, 2 ; <i32> [#uses=1]
ret i32 %D
}
define i32 @or_test1(i32 %X, i32 %Y) {
%A = and i32 %X, 1 ; <i32> [#uses=1]
;; This cannot include any bits from X!
%B = or i32 %A, 1 ; <i32> [#uses=1]
ret i32 %B
}
define i8 @or_test2(i8 %X, i8 %Y) {
%A = shl i8 %X, 7 ; <i8> [#uses=1]
;; This cannot include any bits from X!
%B = or i8 %A, -128 ; <i8> [#uses=1]
ret i8 %B
}