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InstSimplify: Restore optimizations lost in r210006

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This restores our ability to optimize:
(X & C) ? X & ~C : X  into  X & ~C
(X & C) ? X : X & ~C  into  X
(X & C) ? X | C : X  into  X
(X & C) ? X : X | C  into  X | C

llvm-svn: 222868
This commit is contained in:
David Majnemer 2014-11-27 06:32:46 +00:00
parent 3f06ba3b2f
commit d9ae958b9b
3 changed files with 119 additions and 10 deletions
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34
lib/Analysis/InstructionSimplify.cpp
View File

@ -3055,6 +3055,40 @@ static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
if (isa<UndefValue>(FalseVal)) // select C, X, undef -> X
return TrueVal;
if (const auto *ICI = dyn_cast<ICmpInst>(CondVal)) {
Value *X;
const APInt *Y;
if (ICI->isEquality() &&
match(ICI->getOperand(0), m_And(m_Value(X), m_APInt(Y))) &&
match(ICI->getOperand(1), m_Zero())) {
ICmpInst::Predicate Pred = ICI->getPredicate();
const APInt *C;
// (X & Y) == 0 ? X & ~Y : X --> X
// (X & Y) != 0 ? X & ~Y : X --> X & ~Y
if (FalseVal == X && match(TrueVal, m_And(m_Specific(X), m_APInt(C))) &&
*Y == ~*C)
return Pred == ICmpInst::ICMP_EQ ? FalseVal : TrueVal;
// (X & Y) == 0 ? X : X & ~Y --> X & ~Y
// (X & Y) != 0 ? X : X & ~Y --> X
if (TrueVal == X && match(FalseVal, m_And(m_Specific(X), m_APInt(C))) &&
*Y == ~*C)
return Pred == ICmpInst::ICMP_EQ ? FalseVal : TrueVal;
if (Y->isPowerOf2()) {
// (X & Y) == 0 ? X | Y : X --> X | Y
// (X & Y) != 0 ? X | Y : X --> X
if (FalseVal == X && match(TrueVal, m_Or(m_Specific(X), m_APInt(C))) &&
*Y == *C)
return Pred == ICmpInst::ICMP_EQ ? TrueVal : FalseVal;
// (X & Y) == 0 ? X : X | Y --> X
// (X & Y) != 0 ? X : X | Y --> X | Y
if (TrueVal == X && match(FalseVal, m_Or(m_Specific(X), m_APInt(C))) &&
*Y == *C)
return Pred == ICmpInst::ICMP_EQ ? TrueVal : FalseVal;
}
}
}
return nullptr;
}

10
test/Transforms/InstCombine/select.ll
View File

@ -1386,13 +1386,3 @@ entry:
%v = load i128* %p
ret i128 %v
}
define i32 @test87(i32 %x) {
%and = and i32 %x, 1
%cmp = icmp ne i32 %and, 0
%and1 = and i32 %x, -2
%and1.x = select i1 %cmp, i32 %and1, i32 %x
ret i32 %and1.x
; CHECK-LABEL: @test87(
; CHECK: and i32 %x, -2
}

85
test/Transforms/InstSimplify/select.ll Normal file
View File

@ -0,0 +1,85 @@
; RUN: opt < %s -instsimplify -S | FileCheck %s
define i32 @test1(i32 %x) {
%and = and i32 %x, 1
%cmp = icmp eq i32 %and, 0
%and1 = and i32 %x, -2
%and1.x = select i1 %cmp, i32 %and1, i32 %x
ret i32 %and1.x
; CHECK-LABEL: @test1(
; CHECK: ret i32 %x
}
define i32 @test2(i32 %x) {
%and = and i32 %x, 1
%cmp = icmp ne i32 %and, 0
%and1 = and i32 %x, -2
%and1.x = select i1 %cmp, i32 %x, i32 %and1
ret i32 %and1.x
; CHECK-LABEL: @test2(
; CHECK: ret i32 %x
}
define i32 @test3(i32 %x) {
%and = and i32 %x, 1
%cmp = icmp ne i32 %and, 0
%and1 = and i32 %x, -2
%and1.x = select i1 %cmp, i32 %and1, i32 %x
ret i32 %and1.x
; CHECK-LABEL: @test3(
; CHECK: %[[and:.*]] = and i32 %x, -2
; CHECK: ret i32 %[[and]]
}
; CHECK-LABEL: @select_icmp_and_8_eq_0_or_8(
; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
; CHECK-NEXT: ret i32 [[OR]]
define i32 @select_icmp_and_8_eq_0_or_8(i32 %x) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%or = or i32 %x, 8
%or.x = select i1 %cmp, i32 %or, i32 %x
ret i32 %or.x
}
; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8(
; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
; CHECK-NEXT: ret i32 [[AND]]
define i32 @select_icmp_and_8_ne_0_and_not_8(i32 %x) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%and1 = and i32 %x, -9
%x.and1 = select i1 %cmp, i32 %x, i32 %and1
ret i32 %x.and1
}
; CHECK-LABEL: @select_icmp_and_8_eq_0_and_not_8(
; CHECK-NEXT: ret i32 %x
define i32 @select_icmp_and_8_eq_0_and_not_8(i32 %x) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%and1 = and i32 %x, -9
%and1.x = select i1 %cmp, i32 %and1, i32 %x
ret i32 %and1.x
}
; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y_and_not_8(
; CHECK: select i1 %cmp, i64 %y, i64 %and1
define i64 @select_icmp_x_and_8_eq_0_y_and_not_8(i32 %x, i64 %y) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%and1 = and i64 %y, -9
%y.and1 = select i1 %cmp, i64 %y, i64 %and1
ret i64 %y.and1
}
; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_and_not_8(
; CHECK: select i1 %cmp, i64 %and1, i64 %y
define i64 @select_icmp_x_and_8_ne_0_y_and_not_8(i32 %x, i64 %y) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%and1 = and i64 %y, -9
%and1.y = select i1 %cmp, i64 %and1, i64 %y
ret i64 %and1.y
}