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2abe6f500f
simplification in fully optimized code. It occurs sporadically in the testsuite, and many times in 403.gcc: the final bitcode has 131 fewer subtractions after this change. The reason that the multiplies are not eliminated is the same reason that instcombine did not catch this: they are used by other instructions (instcombine catches this with a more general transform which in general is only profitable if the operands have only one use). llvm-svn: 123754
63 lines
1.2 KiB
LLVM
63 lines
1.2 KiB
LLVM
; RUN: opt < %s -instsimplify -S | FileCheck %s
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define i32 @factorize(i32 %x, i32 %y) {
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; CHECK: @factorize
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; (X | 1) & (X | 2) -> X | (1 & 2) -> X
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%l = or i32 %x, 1
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%r = or i32 %x, 2
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%z = and i32 %l, %r
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ret i32 %z
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; CHECK: ret i32 %x
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}
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define i32 @factorize2(i32 %x) {
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; CHECK: @factorize2
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; 3*X - 2*X -> X
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%l = mul i32 3, %x
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%r = mul i32 2, %x
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%z = sub i32 %l, %r
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ret i32 %z
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; CHECK: ret i32 %x
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}
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define i32 @factorize3(i32 %x, i32 %a, i32 %b) {
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; CHECK: @factorize3
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; (X | (A|B)) & (X | B) -> X | ((A|B) & B) -> X | B
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%aORb = or i32 %a, %b
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%l = or i32 %x, %aORb
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%r = or i32 %x, %b
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%z = and i32 %l, %r
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ret i32 %z
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; CHECK: ret i32 %r
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}
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define i32 @factorize4(i32 %x, i32 %y) {
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; CHECK: @factorize4
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%sh = shl i32 %y, 1
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%ml = mul i32 %sh, %x
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%mr = mul i32 %x, %y
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%s = sub i32 %ml, %mr
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ret i32 %s
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; CHECK: ret i32 %mr
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}
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define i32 @factorize5(i32 %x, i32 %y) {
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; CHECK: @factorize5
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%sh = mul i32 %y, 2
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%ml = mul i32 %sh, %x
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%mr = mul i32 %x, %y
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%s = sub i32 %ml, %mr
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ret i32 %s
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; CHECK: ret i32 %mr
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}
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define i32 @expand(i32 %x) {
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; CHECK: @expand
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; ((X & 1) | 2) & 1 -> ((X & 1) & 1) | (2 & 1) -> (X & 1) | 0 -> X & 1
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%a = and i32 %x, 1
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%b = or i32 %a, 2
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%c = and i32 %b, 1
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ret i32 %c
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; CHECK: ret i32 %a
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}
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