maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

InstCombine: Restore optimizations lost in r210006 

This restores our ability to optimize:
(X & C) == 0 ? X ^ C : X  into  X | C
(X & C) != 0 ? X ^ C : X  into  X & ~C

llvm-svn: 222871
This commit is contained in:
David Majnemer 2014-11-27 07:25:21 +00:00
parent 5d50b1a432
commit 40157d5c4d
2 changed files with 81 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
View File

@ -617,6 +617,34 @@ Instruction *InstCombiner::visitSelectInstWithICmp(SelectInst &SI,
}
}
{
Value *X;
const APInt *Y, *C;
if (match(CmpLHS, m_And(m_Value(X), m_Power2(Y))) &&
match(CmpRHS, m_Zero())) {
Value *V = nullptr;
// (X & Y) == 0 ? X : X ^ Y --> X & ~Y
if (Pred == ICmpInst::ICMP_EQ && TrueVal == X &&
match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
V = Builder->CreateAnd(X, ~(*Y));
// (X & Y) != 0 ? X ^ Y : X --> X & ~Y
else if (Pred == ICmpInst::ICMP_NE && FalseVal == X &&
match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
V = Builder->CreateAnd(X, ~(*Y));
// (X & Y) == 0 ? X ^ Y : X --> X | Y
else if (Pred == ICmpInst::ICMP_EQ && FalseVal == X &&
match(TrueVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
V = Builder->CreateOr(X, *Y);
// (X & Y) != 0 ? X : X ^ Y --> X | Y
else if (Pred == ICmpInst::ICMP_NE && TrueVal == X &&
match(FalseVal, m_Xor(m_Specific(X), m_APInt(C))) && *Y == *C)
V = Builder->CreateOr(X, *Y);
if (V)
return ReplaceInstUsesWith(SI, V);
}
}
if (Value *V = foldSelectICmpAndOr(SI, TrueVal, FalseVal, Builder))
return ReplaceInstUsesWith(SI, V);

53
llvm/test/Transforms/InstCombine/select.ll
View File

@ -997,6 +997,59 @@ define <2 x i32> @select_icmp_eq_and_1_0_or_vector_of_2s(i32 %x, <2 x i32> %y) {
ret <2 x i32> %select
}
; CHECK-LABEL: @select_icmp_and_8_ne_0_xor_8(
; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
; CHECK-NEXT: ret i32 [[AND]]
define i32 @select_icmp_and_8_ne_0_xor_8(i32 %x) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%xor = xor i32 %x, 8
%x.xor = select i1 %cmp, i32 %x, i32 %xor
ret i32 %x.xor
}
; CHECK-LABEL: @select_icmp_and_8_eq_0_xor_8(
; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
; CHECK-NEXT: ret i32 [[OR]]
define i32 @select_icmp_and_8_eq_0_xor_8(i32 %x) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%xor = xor i32 %x, 8
%xor.x = select i1 %cmp, i32 %xor, i32 %x
ret i32 %xor.x
}
; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y_xor_8(
; CHECK: select i1 %cmp, i64 %y, i64 %xor
define i64 @select_icmp_x_and_8_eq_0_y_xor_8(i32 %x, i64 %y) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%xor = xor i64 %y, 8
%y.xor = select i1 %cmp, i64 %y, i64 %xor
ret i64 %y.xor
}
; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_xor_8(
; CHECK: select i1 %cmp, i64 %xor, i64 %y
define i64 @select_icmp_x_and_8_ne_0_y_xor_8(i32 %x, i64 %y) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%xor = xor i64 %y, 8
%xor.y = select i1 %cmp, i64 %xor, i64 %y
ret i64 %xor.y
}
; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_or_8(
; CHECK: xor i64 %1, 8
; CHECK: or i64 %2, %y
define i64 @select_icmp_x_and_8_ne_0_y_or_8(i32 %x, i64 %y) {
%and = and i32 %x, 8
%cmp = icmp eq i32 %and, 0
%or = or i64 %y, 8
%or.y = select i1 %cmp, i64 %or, i64 %y
ret i64 %or.y
}
define i32 @test65(i64 %x) {
%1 = and i64 %x, 16
%2 = icmp ne i64 %1, 0