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Asg 2: Mask Reduction for or with Constant (Cayden Lund) (0xFFFFFFFE - (x | 0x7FFFFFFF) → x | 0x7FFFFFFF) (llvm#45)
* [Cayden Lund]: Implement working optimization. Todo: test cases * [Cayden Lund]: Add test cases for optimization
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‎llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

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Original file line numberDiff line numberDiff line change
@@ -5304,6 +5304,32 @@ Instruction* cs6475_optimizer(Instruction *I, InstCombinerImpl &IC, LazyValueInf
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}
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}
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}
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// BEGIN CAYDEN LUND
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// 0xFFFFFFFE - (x | 0x7FFFFFFF) → x | 0x7FFFFFFF
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{
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// Opening new block to allow binding variables of the same name,
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// in order to prevent collisions with other optimizations.
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ConstantInt *C1 = nullptr; // (-2)
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ConstantInt *C2 = nullptr; // (IntMax)
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Value *X = nullptr; // (x)
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Value *Y = nullptr; // (x | IntMax)
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if (match(I, m_Sub(m_ConstantInt(C1), m_Value(Y)))) {
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if (match(Y, m_Or(m_Value(X), m_ConstantInt(C2)))) {
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cs6475_debug("CML: matched 'C1 - (X | C2)'\n");
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if (C1->getValue() == APInt::getMaxValue(C2->getBitWidth()) - 1) {
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cs6475_debug("CML: C1 == -2\n");
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if (C2->getValue() == APInt::getSignedMaxValue(C2->getBitWidth())) {
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cs6475_debug("CML: C2 == IntMax\n");
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log_optzn("Cayden Lund");
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// (x | IntMax)
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return BinaryOperator::CreateOr(X, C2);
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}
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}
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}
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}
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}
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// END CAYDEN LUND
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// BEGIN KHAGAN KARIMOV
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{

‎llvm/test/Transforms/InstCombine/or-constant-mask-reduction.ll

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@@ -0,0 +1,193 @@
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; RUN: opt < %s -passes=instcombine -S | FileCheck %s
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define i8 @test-i8-pos1(i8 %x) {
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%a = or i8 %x, 127
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%b = sub i8 -2, %a
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ret i8 %b
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; CHECK-LABEL: @test-i8-pos1(
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; CHECK-NEXT: [[p1:%.*]] = or i8 %x, 127
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; CHECK-NEXT: ret i8 [[p1]]
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}
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define i8 @test-i8-pos2(i8 %x) {
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%a = or i8 127, %x
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%b = sub i8 -2, %a
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ret i8 %b
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; CHECK-LABEL: @test-i8-pos2(
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; CHECK-NEXT: [[p1:%.*]] = or i8 %x, 127
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; CHECK-NEXT: ret i8 [[p1]]
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}
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define i8 @test-i8-neg1(i8 %x) {
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%a = or i8 %x, 126
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%b = sub i8 -2, %a
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ret i8 %b
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; CHECK-LABEL: @test-i8-neg1(
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; CHECK-NEXT: [[p1:%.*]] = or i8 %x, 126
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; CHECK-NEXT: [[p2:%.*]] = sub i8 -2, [[p1]]
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; CHECK-NEXT: ret i8 [[p2]]
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}
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define i8 @test-i8-neg2(i8 %x) {
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%a = or i8 126, %x
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%b = sub i8 -2, %a
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ret i8 %b
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; CHECK-LABEL: @test-i8-neg2(
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; CHECK-NEXT: [[p1:%.*]] = or i8 %x, 126
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; CHECK-NEXT: [[p2:%.*]] = sub i8 -2, [[p1]]
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; CHECK-NEXT: ret i8 [[p2]]
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}
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define i8 @test-i8-neg3(i8 %x) {
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%a = or i8 %x, 127
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%b = sub i8 0, %a
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ret i8 %b
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; CHECK-LABEL: @test-i8-neg3(
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; CHECK-NEXT: [[p1:%.*]] = or i8 %x, 127
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; CHECK-NEXT: [[p2:%.*]] = sub nsw i8 0, [[p1]]
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; CHECK-NEXT: ret i8 [[p2]]
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}
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define i16 @test-i16-pos1(i16 %x) {
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%a = or i16 %x, 32767
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%b = sub i16 -2, %a
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ret i16 %b
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; CHECK-LABEL: @test-i16-pos1(
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; CHECK-NEXT: [[p1:%.*]] = or i16 %x, 32767
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; CHECK-NEXT: ret i16 [[p1]]
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}
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define i16 @test-i16-pos2(i16 %x) {
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%a = or i16 32767, %x
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%b = sub i16 -2, %a
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ret i16 %b
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; CHECK-LABEL: @test-i16-pos2(
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; CHECK-NEXT: [[p1:%.*]] = or i16 %x, 32767
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; CHECK-NEXT: ret i16 [[p1]]
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}
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define i16 @test-i16-neg1(i16 %x) {
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%a = or i16 %x, 32766
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%b = sub i16 -2, %a
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ret i16 %b
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; CHECK-LABEL: @test-i16-neg1(
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; CHECK-NEXT: [[p1:%.*]] = or i16 %x, 32766
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; CHECK-NEXT: [[p2:%.*]] = sub i16 -2, [[p1]]
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; CHECK-NEXT: ret i16 [[p2]]
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}
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define i16 @test-i16-neg2(i16 %x) {
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%a = or i16 32766, %x
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%b = sub i16 -2, %a
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ret i16 %b
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; CHECK-LABEL: @test-i16-neg2(
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; CHECK-NEXT: [[p1:%.*]] = or i16 %x, 32766
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; CHECK-NEXT: [[p2:%.*]] = sub i16 -2, [[p1]]
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; CHECK-NEXT: ret i16 [[p2]]
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}
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define i16 @test-i16-neg3(i16 %x) {
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%a = or i16 %x, 32767
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%b = sub i16 0, %a
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ret i16 %b
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; CHECK-LABEL: @test-i16-neg3(
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; CHECK-NEXT: [[p1:%.*]] = or i16 %x, 32767
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; CHECK-NEXT: [[p2:%.*]] = sub nsw i16 0, [[p1]]
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; CHECK-NEXT: ret i16 [[p2]]
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}
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define i32 @test-i32-pos1(i32 %x) {
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%a = or i32 %x, 2147483647
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%b = sub i32 -2, %a
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ret i32 %b
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; CHECK-LABEL: @test-i32-pos1(
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; CHECK-NEXT: [[p1:%.*]] = or i32 %x, 2147483647
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; CHECK-NEXT: ret i32 [[p1]]
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}
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define i32 @test-i32-pos2(i32 %x) {
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%a = or i32 2147483647, %x
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%b = sub i32 -2, %a
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ret i32 %b
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; CHECK-LABEL: @test-i32-pos2(
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; CHECK-NEXT: [[p1:%.*]] = or i32 %x, 2147483647
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; CHECK-NEXT: ret i32 [[p1]]
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}
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define i32 @test-i32-neg1(i32 %x) {
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%a = or i32 %x, 2147483646
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%b = sub i32 -2, %a
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ret i32 %b
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; CHECK-LABEL: @test-i32-neg1(
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; CHECK-NEXT: [[p1:%.*]] = or i32 %x, 2147483646
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; CHECK-NEXT: [[p2:%.*]] = sub i32 -2, [[p1]]
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; CHECK-NEXT: ret i32 [[p2]]
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}
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define i32 @test-i32-neg2(i32 %x) {
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%a = or i32 2147483646, %x
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%b = sub i32 -2, %a
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ret i32 %b
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; CHECK-LABEL: @test-i32-neg2(
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; CHECK-NEXT: [[p1:%.*]] = or i32 %x, 2147483646
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; CHECK-NEXT: [[p2:%.*]] = sub i32 -2, [[p1]]
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; CHECK-NEXT: ret i32 [[p2]]
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}
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define i32 @test-i32-neg3(i32 %x) {
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%a = or i32 %x, 2147483647
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%b = sub i32 0, %a
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ret i32 %b
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; CHECK-LABEL: @test-i32-neg3(
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; CHECK-NEXT: [[p1:%.*]] = or i32 %x, 2147483647
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; CHECK-NEXT: [[p2:%.*]] = sub nsw i32 0, [[p1]]
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; CHECK-NEXT: ret i32 [[p2]]
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}
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define i64 @test-i64-pos1(i64 %x) {
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%a = or i64 %x, 9223372036854775807
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%b = sub i64 -2, %a
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ret i64 %b
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; CHECK-LABEL: @test-i64-pos1(
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; CHECK-NEXT: [[p1:%.*]] = or i64 %x, 9223372036854775807
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; CHECK-NEXT: ret i64 [[p1]]
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}
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define i64 @test-i64-pos2(i64 %x) {
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%a = or i64 9223372036854775807, %x
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%b = sub i64 -2, %a
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ret i64 %b
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; CHECK-LABEL: @test-i64-pos2(
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; CHECK-NEXT: [[p1:%.*]] = or i64 %x, 9223372036854775807
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; CHECK-NEXT: ret i64 [[p1]]
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}
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define i64 @test-i64-neg1(i64 %x) {
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%a = or i64 %x, 9223372036854775806
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%b = sub i64 -2, %a
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ret i64 %b
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; CHECK-LABEL: @test-i64-neg1(
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; CHECK-NEXT: [[p1:%.*]] = or i64 %x, 9223372036854775806
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; CHECK-NEXT: [[p2:%.*]] = sub i64 -2, [[p1]]
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; CHECK-NEXT: ret i64 [[p2]]
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}
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define i64 @test-i64-neg2(i64 %x) {
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%a = or i64 9223372036854775806, %x
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%b = sub i64 -2, %a
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ret i64 %b
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; CHECK-LABEL: @test-i64-neg2(
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; CHECK-NEXT: [[p1:%.*]] = or i64 %x, 9223372036854775806
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; CHECK-NEXT: [[p2:%.*]] = sub i64 -2, [[p1]]
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; CHECK-NEXT: ret i64 [[p2]]
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}
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define i64 @test-i64-neg3(i64 %x) {
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%a = or i64 %x, 9223372036854775807
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%b = sub i64 0, %a
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ret i64 %b
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; CHECK-LABEL: @test-i64-neg3(
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; CHECK-NEXT: [[p1:%.*]] = or i64 %x, 9223372036854775807
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; CHECK-NEXT: [[p2:%.*]] = sub nsw i64 0, [[p1]]
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; CHECK-NEXT: ret i64 [[p2]]
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}

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