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InstCombine: X & -C != -C -> X <= u ~C

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Tests were added in r185910 somehow.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185912 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
David Majnemer 2013-07-09 08:09:32 +00:00
parent ff16df71f5
commit 36b6f7409d
2 changed files with 9 additions and 40 deletions
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9
lib/Transforms/InstCombine/InstCombineCompares.cpp
View File

@ -1277,6 +1277,15 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
return Res;
}
}
// X & -C == -C -> X > u ~C
// X & -C != -C -> X <= u ~C
// iff C is a power of 2
if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2())
return new ICmpInst(
ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT
: ICmpInst::ICMP_ULE,
LHSI->getOperand(0), SubOne(RHS));
break;
case Instruction::Or: {

40
test/Transforms/InstCombine/icmp.ll
View File

@ -1164,46 +1164,6 @@ define i1 @icmp_sub_3_X_uge_2(i32 %X) {
ret i1 %cmp
}
; CHECK: @icmp_add_X_-14_ult_2
; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %X, -2
; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp eq i32 [[AND]], 14
; CHECK-NEXT: ret i1 [[CMP]]
define i1 @icmp_add_X_-14_ult_2(i32 %X) {
%add = add i32 %X, -14
%cmp = icmp ult i32 %add, 2
ret i1 %cmp
}
; CHECK: @icmp_sub_3_X_ult_2
; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %X, 1
; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp eq i32 [[OR]], 3
; CHECK-NEXT: ret i1 [[CMP]]
define i1 @icmp_sub_3_X_ult_2(i32 %X) {
%add = sub i32 3, %X
%cmp = icmp ult i32 %add, 2
ret i1 %cmp
}
; CHECK: @icmp_add_X_-14_uge_2
; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %X, -2
; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp ne i32 [[AND]], 14
; CHECK-NEXT: ret i1 [[CMP]]
define i1 @icmp_add_X_-14_uge_2(i32 %X) {
%add = add i32 %X, -14
%cmp = icmp uge i32 %add, 2
ret i1 %cmp
}
; CHECK: @icmp_sub_3_X_uge_2
; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %X, 1
; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp ne i32 [[OR]], 3
; CHECK-NEXT: ret i1 [[CMP]]
define i1 @icmp_sub_3_X_uge_2(i32 %X) {
%add = sub i32 3, %X
%cmp = icmp uge i32 %add, 2
ret i1 %cmp
}
; CHECK: @icmp_and_X_-16_eq-16
; CHECK-NEXT: [[CMP:%[a-z0-9]+]] = icmp ugt i32 %X, -17
; CHECK-NEXT: ret i1 [[CMP]]