[llvm] r211881 - Added instruction combine to transform few more negative values addition to subtraction (Part 3)
Dinesh Dwivedi
dinesh.d at samsung.com
Fri Jun 27 00:47:35 PDT 2014
Author: dinesh
Date: Fri Jun 27 02:47:35 2014
New Revision: 211881
URL: http://llvm.org/viewvc/llvm-project?rev=211881&view=rev
Log:
Added instruction combine to transform few more negative values addition to subtraction (Part 3)
This patch enables transforms for
(x + (~(y | c) + 1) --> x - (y | c) if c is odd
Differential Revision: http://reviews.llvm.org/D4210
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
llvm/trunk/test/Transforms/InstCombine/add2.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp?rev=211881&r1=211880&r2=211881&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineAddSub.cpp Fri Jun 27 02:47:35 2014
@@ -954,56 +954,70 @@ bool InstCombiner::WillNotOverflowUnsign
return true;
return false;
- }
+}
// Checks if any operand is negative and we can convert add to sub.
- // This function checks for following negative patterns
- // ADD(XOR(OR(Z, NOT(C)), C)), 1) == NEG(AND(Z, C))
- // ADD(XOR(AND(Z, C), C), 1) == NEG(OR(Z, ~C)) if C is odd
- // TODO: XOR(AND(Z, C), (C + 1)) == NEG(OR(Z, ~C)) if C is even
- Value *checkForNegativeOperand(BinaryOperator &I,
- InstCombiner::BuilderTy *Builder) {
- Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
+// This function checks for following negative patterns
+// ADD(XOR(OR(Z, NOT(C)), C)), 1) == NEG(AND(Z, C))
+// ADD(XOR(AND(Z, C), C), 1) == NEG(OR(Z, ~C))
+// XOR(AND(Z, C), (C + 1)) == NEG(OR(Z, ~C)) if C is even
+Value *checkForNegativeOperand(BinaryOperator &I,
+ InstCombiner::BuilderTy *Builder) {
+ Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
- // This function creates 2 instructions to replace ADD, we need at least one
- // of LHS or RHS to have one use to ensure benefit in transform.
- if (!LHS->hasOneUse() && !RHS->hasOneUse())
- return nullptr;
-
- Value *X = nullptr, *Y = nullptr, *Z = nullptr;
- const APInt *C1 = nullptr, *C2 = nullptr;
-
- // if ONE is on other side, swap
- if (match(RHS, m_Add(m_Value(X), m_One())))
- std::swap(LHS, RHS);
-
- if (match(LHS, m_Add(m_Value(X), m_One()))) {
- // if XOR on other side, swap
- if (match(RHS, m_Xor(m_Value(Y), m_APInt(C1))))
- std::swap(X, RHS);
-
- if (match(X, m_Xor(m_Value(Y), m_APInt(C1)))) {
- // X = XOR(Y, C1), Y = OR(Z, C2), C2 = NOT(C1) ==> X == NOT(AND(Z, C1))
- // ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, AND(Z, C1))
- if (match(Y, m_Or(m_Value(Z), m_APInt(C2))) && (*C2 == ~(*C1))) {
- Value *NewAnd = Builder->CreateAnd(Z, *C1);
- return Builder->CreateSub(RHS, NewAnd, "sub");
- } else if (C1->countTrailingZeros() == 0) {
- // if C1 is ODD and
- // X = XOR(Y, C1), Y = AND(Z, C2), C2 == C1 ==> X == NOT(OR(Z, ~C1))
- // ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, OR(Z, ~C1))
- if (match(Y, m_And(m_Value(Z), m_APInt(C2))) && (*C1 == *C2)) {
- Value *NewOr = Builder->CreateOr(Z, ~(*C1));
- return Builder->CreateSub(RHS, NewOr, "sub");
- }
- }
- }
- }
+ // This function creates 2 instructions to replace ADD, we need at least one
+ // of LHS or RHS to have one use to ensure benefit in transform.
+ if (!LHS->hasOneUse() && !RHS->hasOneUse())
+ return nullptr;
+
+ Value *X = nullptr, *Y = nullptr, *Z = nullptr;
+ const APInt *C1 = nullptr, *C2 = nullptr;
+
+ // if ONE is on other side, swap
+ if (match(RHS, m_Add(m_Value(X), m_One())))
+ std::swap(LHS, RHS);
+
+ if (match(LHS, m_Add(m_Value(X), m_One()))) {
+ // if XOR on other side, swap
+ if (match(RHS, m_Xor(m_Value(Y), m_APInt(C1))))
+ std::swap(X, RHS);
+
+ if (match(X, m_Xor(m_Value(Y), m_APInt(C1)))) {
+ // X = XOR(Y, C1), Y = OR(Z, C2), C2 = NOT(C1) ==> X == NOT(AND(Z, C1))
+ // ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, AND(Z, C1))
+ if (match(Y, m_Or(m_Value(Z), m_APInt(C2))) && (*C2 == ~(*C1))) {
+ Value *NewAnd = Builder->CreateAnd(Z, *C1);
+ return Builder->CreateSub(RHS, NewAnd, "sub");
+ } else if (match(Y, m_And(m_Value(Z), m_APInt(C2))) && (*C1 == *C2)) {
+ // X = XOR(Y, C1), Y = AND(Z, C2), C2 == C1 ==> X == NOT(OR(Z, ~C1))
+ // ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, OR(Z, ~C1))
+ Value *NewOr = Builder->CreateOr(Z, ~(*C1));
+ return Builder->CreateSub(RHS, NewOr, "sub");
+ }
+ }
+ }
- return nullptr;
- }
+ // Restore LHS and RHS
+ LHS = I.getOperand(0);
+ RHS = I.getOperand(1);
+
+ // if XOR is on other side, swap
+ if (match(RHS, m_Xor(m_Value(Y), m_APInt(C1))))
+ std::swap(LHS, RHS);
+
+ // C2 is ODD
+ // LHS = XOR(Y, C1), Y = AND(Z, C2), C1 == (C2 + 1) => LHS == NEG(OR(Z, ~C2))
+ // ADD(LHS, RHS) == SUB(RHS, OR(Z, ~C2))
+ if (match(LHS, m_Xor(m_Value(Y), m_APInt(C1))))
+ if (C1->countTrailingZeros() == 0)
+ if (match(Y, m_And(m_Value(Z), m_APInt(C2))) && *C1 == (*C2 + 1)) {
+ Value *NewOr = Builder->CreateOr(Z, ~(*C2));
+ return Builder->CreateSub(RHS, NewOr, "sub");
+ }
+ return nullptr;
+}
- Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
+Instruction *InstCombiner::visitAdd(BinaryOperator &I) {
bool Changed = SimplifyAssociativeOrCommutative(I);
Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
@@ -1579,7 +1593,7 @@ Instruction *InstCombiner::visitSub(Bina
match(Op1, m_Trunc(m_PtrToInt(m_Value(RHSOp)))))
if (Value *Res = OptimizePointerDifference(LHSOp, RHSOp, I.getType()))
return ReplaceInstUsesWith(I, Res);
- }
+ }
return nullptr;
}
Modified: llvm/trunk/test/Transforms/InstCombine/add2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/add2.ll?rev=211881&r1=211880&r2=211881&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/add2.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/add2.ll Fri Jun 27 02:47:35 2014
@@ -87,17 +87,22 @@ define i16 @test9(i16 %a) {
; CHECK-NEXT: ret i16 %d
}
-define i32 @test10(i32 %x) {
- %x.not = or i32 %x, -1431655766
- %neg = xor i32 %x.not, 1431655765
- %add = add i32 %x, 1
+; y + (~((x >> 3) & 0x55555555) + 1) -> y - ((x >> 3) & 0x55555555)
+define i32 @test10(i32 %x, i32 %y) {
+ %shr = ashr i32 %x, 3
+ %shr.not = or i32 %shr, -1431655766
+ %neg = xor i32 %shr.not, 1431655765
+ %add = add i32 %y, 1
%add1 = add i32 %add, %neg
ret i32 %add1
; CHECK-LABEL: @test10(
-; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -1431655766
-; CHECK-NEXT: ret i32 [[AND]]
+; CHECK-NEXT: [[SHR:%[a-z0-9]+]] = ashr i32 %x, 3
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 [[SHR]], 1431655765
+; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
+; CHECK-NEXT: ret i32 [[SUB]]
}
+; y + (~(x & 0x55555555) + 1) -> y - (x & 0x55555555)
define i32 @test11(i32 %x, i32 %y) {
%x.not = or i32 %x, -1431655766
%neg = xor i32 %x.not, 1431655765
@@ -110,20 +115,20 @@ define i32 @test11(i32 %x, i32 %y) {
; CHECK-NEXT: ret i32 [[SUB]]
}
+; (y + 1) + ~(x & 0x55555555) -> y - (x & 0x55555555)
define i32 @test12(i32 %x, i32 %y) {
- %shr = ashr i32 %x, 3
- %shr.not = or i32 %shr, -1431655766
- %neg = xor i32 %shr.not, 1431655765
- %add = add i32 %y, 1
- %add1 = add i32 %add, %neg
+ %add = add nsw i32 %y, 1
+ %x.not = or i32 %x, -1431655766
+ %neg = xor i32 %x.not, 1431655765
+ %add1 = add nsw i32 %add, %neg
ret i32 %add1
; CHECK-LABEL: @test12(
-; CHECK-NEXT: [[SHR:%[a-z0-9]+]] = ashr i32 %x, 3
-; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 [[SHR]], 1431655765
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, 1431655765
; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
; CHECK-NEXT: ret i32 [[SUB]]
}
+; y + (~(x & 0x55555556) + 1) -> y - (x & 0x55555556)
define i32 @test13(i32 %x, i32 %y) {
%x.not = or i32 %x, -1431655767
%neg = xor i32 %x.not, 1431655766
@@ -136,43 +141,67 @@ define i32 @test13(i32 %x, i32 %y) {
; CHECK-NEXT: ret i32 [[SUB]]
}
+; (y + 1) + ~(x & 0x55555556) -> y - (x & 0x55555556)
define i32 @test14(i32 %x, i32 %y) {
- %shr = ashr i32 %x, 3
- %shr.not = or i32 %shr, -1431655767
- %neg = xor i32 %shr.not, 1431655766
- %add = add i32 %y, 1
- %add1 = add i32 %add, %neg
+ %add = add nsw i32 %y, 1
+ %x.not = or i32 %x, -1431655767
+ %neg = xor i32 %x.not, 1431655766
+ %add1 = add nsw i32 %add, %neg
ret i32 %add1
; CHECK-LABEL: @test14(
-; CHECK-NEXT: [[SHR:%[a-z0-9]+]] = ashr i32 %x, 3
-; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 [[SHR]], 1431655766
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, 1431655766
; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
; CHECK-NEXT: ret i32 [[SUB]]
}
+; y + (~(x | 0x55555556) + 1) -> y - (x | 0x55555556)
define i32 @test15(i32 %x, i32 %y) {
- %x.not = and i32 %x, -1431655767
- %neg = xor i32 %x.not, -1431655767
- %add = add i32 %y, 1
- %add1 = add i32 %add, %neg
- ret i32 %add1
+ %x.not = and i32 %x, -1431655767
+ %neg = xor i32 %x.not, -1431655767
+ %add = add i32 %y, 1
+ %add1 = add i32 %add, %neg
+ ret i32 %add1
; CHECK-LABEL: @test15(
-; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 1431655766
-; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[OR]]
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = or i32 %x, 1431655766
+; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
; CHECK-NEXT: ret i32 [[SUB]]
}
+; (y + 1) + ~(x | 0x55555556) -> y - (x | 0x555555556)
define i32 @test16(i32 %x, i32 %y) {
- %shr = ashr i32 %x, 3
- %shr.not = and i32 %shr, -1431655767
- %neg = xor i32 %shr.not, -1431655767
- %add = add i32 %y, 1
- %add1 = add i32 %add, %neg
- ret i32 %add1
+ %add = add nsw i32 %y, 1
+ %x.not = and i32 %x, -1431655767
+ %neg = xor i32 %x.not, -1431655767
+ %add1 = add nsw i32 %add, %neg
+ ret i32 %add1
; CHECK-LABEL: @test16(
-; CHECK-NEXT: [[SHR:%[a-z0-9]+]] = ashr i32 %x, 3
-; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 [[SHR]], 1431655766
-; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[OR]]
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = or i32 %x, 1431655766
+; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
+; CHECK-NEXT: ret i32 [[SUB]]
+}
+
+; y + (~(x | 0x55555555) + 1) -> y - (x | 0x55555555)
+define i32 @test17(i32 %x, i32 %y) {
+ %x.not = and i32 %x, -1431655766
+ %add2 = xor i32 %x.not, -1431655765
+ %add1 = add nsw i32 %add2, %y
+ ret i32 %add1
+; CHECK-LABEL: @test17(
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = or i32 %x, 1431655765
+; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
+; CHECK-NEXT: ret i32 [[SUB]]
+}
+
+; (y + 1) + ~(x | 0x55555555) -> y - (x | 0x55555555)
+define i32 @test18(i32 %x, i32 %y) {
+ %add = add nsw i32 %y, 1
+ %x.not = and i32 %x, -1431655766
+ %neg = xor i32 %x.not, -1431655766
+ %add1 = add nsw i32 %add, %neg
+ ret i32 %add1
+; CHECK-LABEL: @test18(
+; CHECK-NEXT: [[AND:%[a-z0-9]+]] = or i32 %x, 1431655765
+; CHECK-NEXT: [[SUB:%[a-z0-9]+]] = sub i32 %y, [[AND]]
; CHECK-NEXT: ret i32 [[SUB]]
}
More information about the llvm-commits
mailing list