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New testcase for common bitfield manipulation instruction sequences.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19218 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-01-01 16:14:18 +00:00
parent 296fcbaf2c
commit 095b51ee36
1 changed files with 54 additions and 0 deletions
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54
test/Transforms/InstCombine/and-or-and.ll Normal file
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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.
; RUN: llvm-as < %s | opt -instcombine | llvm-dis | not grep 'or '
int %test1(int %X, int %Y) {
%A = and int %X, 7
%B = and int %Y, 8
%C = or int %A, %B
%D = and int %C, 7 ;; This cannot include any bits from %Y!
ret int %D
}
int %test2(int %X, ubyte %Y) {
%B = cast ubyte %Y to int
%C = or int %X, %B
%D = and int %C, 65536 ;; This cannot include any bits from %Y!
ret int %D
}
int %test3(int %X, int %Y) {
%B = shl int %Y, ubyte 1
%C = or int %X, %B
%D = and int %C, 1 ;; This cannot include any bits from %Y!
ret int %D
}
uint %test4(uint %X, uint %Y) {
%B = shr uint %Y, ubyte 31
%C = or uint %X, %B
%D = and uint %C, 2 ;; This cannot include any bits from %Y!
ret uint %D
}
int %or_test1(int %X, int %Y) {
%A = and int %X, 1
%B = or int %A, 1 ;; This cannot include any bits from X!
ret int %B
}
ubyte %or_test2(ubyte %X, ubyte %Y) {
%A = shl ubyte %X, ubyte 7
%B = or ubyte %A, 128 ;; This cannot include any bits from X!
ret ubyte %B
}