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