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-rw-r--r--llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp35
-rw-r--r--llvm/test/Transforms/InstCombine/icmp.ll126
-rw-r--r--llvm/test/Transforms/InstCombine/sub.ll2
3 files changed, 143 insertions, 20 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index f1533ce9fe5..999de340975 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -2267,7 +2267,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
return new ICmpInst(Pred, Constant::getNullValue(Op0->getType()),
C == Op0 ? D : C);
- // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
+ // icmp (X+Y), (X+Z) -> icmp Y, Z for equalities or if there is no overflow.
if (A && C && (A == C || A == D || B == C || B == D) &&
NoOp0WrapProblem && NoOp1WrapProblem &&
// Try not to increase register pressure.
@@ -2286,12 +2286,26 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
if (BO1 && BO1->getOpcode() == Instruction::Sub)
C = BO1->getOperand(0), D = BO1->getOperand(1);
- // icmp (Y-X), (Z-X) -> icmp Y,Z for equalities or if there is no overflow.
+ // icmp (X-Y), X -> icmp 0, Y for equalities or if there is no overflow.
+ if (A == Op1 && NoOp0WrapProblem)
+ return new ICmpInst(Pred, Constant::getNullValue(Op1->getType()), B);
+
+ // icmp X, (X-Y) -> icmp Y, 0 for equalities or if there is no overflow.
+ if (C == Op0 && NoOp1WrapProblem)
+ return new ICmpInst(Pred, D, Constant::getNullValue(Op0->getType()));
+
+ // icmp (Y-X), (Z-X) -> icmp Y, Z for equalities or if there is no overflow.
if (B && D && B == D && NoOp0WrapProblem && NoOp1WrapProblem &&
// Try not to increase register pressure.
BO0->hasOneUse() && BO1->hasOneUse())
return new ICmpInst(Pred, A, C);
+ // icmp (X-Y), (X-Z) -> icmp Z, Y for equalities or if there is no overflow.
+ if (A && C && A == C && NoOp0WrapProblem && NoOp1WrapProblem &&
+ // Try not to increase register pressure.
+ BO0->hasOneUse() && BO1->hasOneUse())
+ return new ICmpInst(Pred, D, B);
+
if (BO0 && BO1 && BO0->getOpcode() == BO1->getOpcode() &&
BO0->hasOneUse() && BO1->hasOneUse() &&
BO0->getOperand(1) == BO1->getOperand(1)) {
@@ -2375,12 +2389,7 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
if (I.isEquality()) {
Value *A, *B, *C, *D;
-
- // -x == -y --> x == y
- if (match(Op0, m_Neg(m_Value(A))) &&
- match(Op1, m_Neg(m_Value(B))))
- return new ICmpInst(I.getPredicate(), A, B);
-
+
if (match(Op0, m_Xor(m_Value(A), m_Value(B)))) {
if (A == Op1 || B == Op1) { // (A^B) == A -> B == 0
Value *OtherVal = A == Op1 ? B : A;
@@ -2415,16 +2424,6 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) {
Constant::getNullValue(A->getType()));
}
- // (A-B) == A -> B == 0
- if (match(Op0, m_Sub(m_Specific(Op1), m_Value(B))))
- return new ICmpInst(I.getPredicate(), B,
- Constant::getNullValue(B->getType()));
-
- // A == (A-B) -> B == 0
- if (match(Op1, m_Sub(m_Specific(Op0), m_Value(B))))
- return new ICmpInst(I.getPredicate(), B,
- Constant::getNullValue(B->getType()));
-
// (X&Z) == (Y&Z) -> (X^Y) & Z == 0
if (Op0->hasOneUse() && Op1->hasOneUse() &&
match(Op0, m_And(m_Value(A), m_Value(B))) &&
diff --git a/llvm/test/Transforms/InstCombine/icmp.ll b/llvm/test/Transforms/InstCombine/icmp.ll
index 08718affa02..3150883e7d7 100644
--- a/llvm/test/Transforms/InstCombine/icmp.ll
+++ b/llvm/test/Transforms/InstCombine/icmp.ll
@@ -235,6 +235,7 @@ define i1 @test24(i64 %i) {
}
; CHECK: @test25
+; X + Z > Y + Z -> X > Y if there is no overflow.
; CHECK: %c = icmp sgt i32 %x, %y
; CHECK: ret i1 %c
define i1 @test25(i32 %x, i32 %y, i32 %z) {
@@ -245,11 +246,134 @@ define i1 @test25(i32 %x, i32 %y, i32 %z) {
}
; CHECK: @test26
-; CHECK: %c = icmp sgt i32 %x, %y
+; X + Z > Y + Z -> X > Y if there is no overflow.
+; CHECK: %c = icmp ugt i32 %x, %y
; CHECK: ret i1 %c
define i1 @test26(i32 %x, i32 %y, i32 %z) {
+ %lhs = add nuw i32 %x, %z
+ %rhs = add nuw i32 %y, %z
+ %c = icmp ugt i32 %lhs, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test27
+; X - Z > Y - Z -> X > Y if there is no overflow.
+; CHECK: %c = icmp sgt i32 %x, %y
+; CHECK: ret i1 %c
+define i1 @test27(i32 %x, i32 %y, i32 %z) {
%lhs = sub nsw i32 %x, %z
%rhs = sub nsw i32 %y, %z
%c = icmp sgt i32 %lhs, %rhs
ret i1 %c
}
+
+; CHECK: @test28
+; X - Z > Y - Z -> X > Y if there is no overflow.
+; CHECK: %c = icmp ugt i32 %x, %y
+; CHECK: ret i1 %c
+define i1 @test28(i32 %x, i32 %y, i32 %z) {
+ %lhs = sub nuw i32 %x, %z
+ %rhs = sub nuw i32 %y, %z
+ %c = icmp ugt i32 %lhs, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test29
+; X + Y > X -> Y > 0 if there is no overflow.
+; CHECK: %c = icmp sgt i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test29(i32 %x, i32 %y) {
+ %lhs = add nsw i32 %x, %y
+ %c = icmp sgt i32 %lhs, %x
+ ret i1 %c
+}
+
+; CHECK: @test30
+; X + Y > X -> Y > 0 if there is no overflow.
+; CHECK: %c = icmp ne i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test30(i32 %x, i32 %y) {
+ %lhs = add nuw i32 %x, %y
+ %c = icmp ugt i32 %lhs, %x
+ ret i1 %c
+}
+
+; CHECK: @test31
+; X > X + Y -> 0 > Y if there is no overflow.
+; CHECK: %c = icmp slt i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test31(i32 %x, i32 %y) {
+ %rhs = add nsw i32 %x, %y
+ %c = icmp sgt i32 %x, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test32
+; X > X + Y -> 0 > Y if there is no overflow.
+; CHECK: ret i1 false
+define i1 @test32(i32 %x, i32 %y) {
+ %rhs = add nuw i32 %x, %y
+ %c = icmp ugt i32 %x, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test33
+; X - Y > X -> 0 > Y if there is no overflow.
+; CHECK: %c = icmp slt i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test33(i32 %x, i32 %y) {
+ %lhs = sub nsw i32 %x, %y
+ %c = icmp sgt i32 %lhs, %x
+ ret i1 %c
+}
+
+; CHECK: @test34
+; X - Y > X -> 0 > Y if there is no overflow.
+; CHECK: ret i1 false
+define i1 @test34(i32 %x, i32 %y) {
+ %lhs = sub nuw i32 %x, %y
+ %c = icmp ugt i32 %lhs, %x
+ ret i1 %c
+}
+
+; CHECK: @test35
+; X > X - Y -> Y > 0 if there is no overflow.
+; CHECK: %c = icmp sgt i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test35(i32 %x, i32 %y) {
+ %rhs = sub nsw i32 %x, %y
+ %c = icmp sgt i32 %x, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test36
+; X > X - Y -> Y > 0 if there is no overflow.
+; CHECK: %c = icmp ne i32 %y, 0
+; CHECK: ret i1 %c
+define i1 @test36(i32 %x, i32 %y) {
+ %rhs = sub nuw i32 %x, %y
+ %c = icmp ugt i32 %x, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test37
+; X - Y > X - Z -> Z > Y if there is no overflow.
+; CHECK: %c = icmp sgt i32 %z, %y
+; CHECK: ret i1 %c
+define i1 @test37(i32 %x, i32 %y, i32 %z) {
+ %lhs = sub nsw i32 %x, %y
+ %rhs = sub nsw i32 %x, %z
+ %c = icmp sgt i32 %lhs, %rhs
+ ret i1 %c
+}
+
+; CHECK: @test38
+; X - Y > X - Z -> Z > Y if there is no overflow.
+; CHECK: %c = icmp ugt i32 %z, %y
+; CHECK: ret i1 %c
+define i1 @test38(i32 %x, i32 %y, i32 %z) {
+ %lhs = sub nuw i32 %x, %y
+ %rhs = sub nuw i32 %x, %z
+ %c = icmp ugt i32 %lhs, %rhs
+ ret i1 %c
+}
diff --git a/llvm/test/Transforms/InstCombine/sub.ll b/llvm/test/Transforms/InstCombine/sub.ll
index 778a1b9db5d..9656a7e862a 100644
--- a/llvm/test/Transforms/InstCombine/sub.ll
+++ b/llvm/test/Transforms/InstCombine/sub.ll
@@ -209,7 +209,7 @@ define i1 @test22(i32 %a, i32 %b) zeroext nounwind {
%tmp5 = icmp eq i32 %tmp2, %tmp4
ret i1 %tmp5
; CHECK: @test22
-; CHECK: %tmp5 = icmp eq i32 %a, %b
+; CHECK: %tmp5 = icmp eq i32 %b, %a
; CHECK: ret i1 %tmp5
}
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