[llvm] r364341 - [InstCombine] reduce checks for power-of-2-or-zero using ctpop
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 25 11:51:44 PDT 2019
Author: spatel
Date: Tue Jun 25 11:51:44 2019
New Revision: 364341
URL: http://llvm.org/viewvc/llvm-project?rev=364341&view=rev
Log:
[InstCombine] reduce checks for power-of-2-or-zero using ctpop
This follows up the transform from rL363956 to use the ctpop intrinsic when checking for power-of-2-or-zero.
This is matching the isPowerOf2() patterns used in PR42314:
https://bugs.llvm.org/show_bug.cgi?id=42314
But there's at least 1 instcombine follow-up needed to match the alternate form:
(v & (v - 1)) == 0;
We should have all of the backend expansions handled with:
rL364319
(x86-specific changes still needed for optimal code based on subtarget)
And the larger patterns to exclude zero as a power-of-2 are joining with this change after:
rL364153 ( D63660 )
rL364246
Differential Revision: https://reviews.llvm.org/D63777
Modified:
llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
llvm/trunk/test/Transforms/InstCombine/ispow2.ll
Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp?rev=364341&r1=364340&r2=364341&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Tue Jun 25 11:51:44 2019
@@ -3829,23 +3829,21 @@ Instruction *InstCombiner::foldICmpEqual
return new ICmpInst(Pred, A, B);
// Canonicalize checking for a power-of-2-or-zero value:
- // (A & -A) == A --> (A & (A - 1)) == 0
- // (-A & A) == A --> (A & (A - 1)) == 0
- // A == (A & -A) --> (A & (A - 1)) == 0
- // A == (-A & A) --> (A & (A - 1)) == 0
- // TODO: This could be reduced by using the ctpop intrinsic.
+ // (A & -A) == A --> ctpop(A) < 2 (four commuted variants)
+ // (-A & A) != A --> ctpop(A) > 1 (four commuted variants)
A = nullptr;
- if (match(Op0, m_OneUse(m_c_And(m_OneUse(m_Neg(m_Specific(Op1))),
- m_Specific(Op1)))))
+ if (match(Op0, m_OneUse(m_c_And(m_Neg(m_Specific(Op1)), m_Specific(Op1)))))
A = Op1;
- else if (match(Op1, m_OneUse(m_c_And(m_OneUse(m_Neg(m_Specific(Op0))),
- m_Specific(Op0)))))
+ else if (match(Op1,
+ m_OneUse(m_c_And(m_Neg(m_Specific(Op0)), m_Specific(Op0)))))
A = Op0;
+
if (A) {
Type *Ty = A->getType();
- Value *Dec = Builder.CreateAdd(A, ConstantInt::getAllOnesValue(Ty));
- Value *And = Builder.CreateAnd(A, Dec);
- return new ICmpInst(Pred, And, ConstantInt::getNullValue(Ty));
+ CallInst *CtPop = Builder.CreateUnaryIntrinsic(Intrinsic::ctpop, A);
+ return Pred == ICmpInst::ICMP_EQ
+ ? new ICmpInst(ICmpInst::ICMP_ULT, CtPop, ConstantInt::get(Ty, 2))
+ : new ICmpInst(ICmpInst::ICMP_UGT, CtPop, ConstantInt::get(Ty, 1));
}
return nullptr;
Modified: llvm/trunk/test/Transforms/InstCombine/ispow2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/ispow2.ll?rev=364341&r1=364340&r2=364341&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/ispow2.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/ispow2.ll Tue Jun 25 11:51:44 2019
@@ -3,9 +3,8 @@
define i1 @is_pow2or0_negate_op(i32 %x) {
; CHECK-LABEL: @is_pow2or0_negate_op(
-; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[TMP2]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range !0
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[TMP1]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
%neg = sub i32 0, %x
@@ -16,9 +15,8 @@ define i1 @is_pow2or0_negate_op(i32 %x)
define <2 x i1> @is_pow2or0_negate_op_vec(<2 x i32> %x) {
; CHECK-LABEL: @is_pow2or0_negate_op_vec(
-; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i32> [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i32> [[TMP2]], zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i32> [[TMP1]], <i32 2, i32 2>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%neg = sub <2 x i32> zeroinitializer, %x
@@ -55,9 +53,8 @@ define <2 x i1> @is_pow2or0_decrement_op
define i1 @isnot_pow2or0_negate_op(i32 %x) {
; CHECK-LABEL: @isnot_pow2or0_negate_op(
-; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range !0
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
%neg = sub i32 0, %x
@@ -68,9 +65,8 @@ define i1 @isnot_pow2or0_negate_op(i32 %
define <2 x i1> @isnot_pow2or0_negate_op_vec(<2 x i32> %x) {
; CHECK-LABEL: @isnot_pow2or0_negate_op_vec(
-; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i32> [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[TMP2]], zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i32> [[TMP1]], <i32 1, i32 1>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%neg = sub <2 x i32> zeroinitializer, %x
@@ -108,9 +104,8 @@ define <2 x i1> @isnot_pow2or0_decrement
define i1 @is_pow2or0_negate_op_commute1(i32 %p) {
; CHECK-LABEL: @is_pow2or0_negate_op_commute1(
; CHECK-NEXT: [[X:%.*]] = srem i32 42, [[P:%.*]]
-; CHECK-NEXT: [[TMP1:%.*]] = add nsw i32 [[X]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[X]], [[TMP1]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[TMP2]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[TMP1]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
%x = srem i32 42, %p ; thwart complexity-based canonicalization
@@ -125,9 +120,8 @@ define i1 @is_pow2or0_negate_op_commute1
define i1 @isnot_pow2or0_negate_op_commute2(i32 %p) {
; CHECK-LABEL: @isnot_pow2or0_negate_op_commute2(
; CHECK-NEXT: [[X:%.*]] = urem i32 42, [[P:%.*]]
-; CHECK-NEXT: [[TMP1:%.*]] = add nsw i32 [[X]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[X]], [[TMP1]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !2
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
%x = urem i32 42, %p ; thwart complexity-based canonicalization
@@ -140,9 +134,8 @@ define i1 @isnot_pow2or0_negate_op_commu
define i1 @isnot_pow2or0_negate_op_commute3(i32 %p) {
; CHECK-LABEL: @isnot_pow2or0_negate_op_commute3(
; CHECK-NEXT: [[X:%.*]] = urem i32 42, [[P:%.*]]
-; CHECK-NEXT: [[TMP1:%.*]] = add nsw i32 [[X]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[X]], [[TMP1]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[TMP2]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !2
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
%x = urem i32 42, %p ; thwart complexity-based canonicalization
@@ -158,8 +151,8 @@ define i1 @is_pow2or0_negate_op_extra_us
; CHECK-LABEL: @is_pow2or0_negate_op_extra_use1(
; CHECK-NEXT: [[NEG:%.*]] = sub i32 0, [[X:%.*]]
; CHECK-NEXT: call void @use(i32 [[NEG]])
-; CHECK-NEXT: [[AND:%.*]] = and i32 [[NEG]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[AND]], [[X]]
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !0
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[TMP1]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
%neg = sub i32 0, %x
@@ -428,12 +421,9 @@ define i1 @isnot_pow2_ctpop_wrong_pred2(
define i1 @is_pow2_negate_op(i32 %x) {
; CHECK-LABEL: @is_pow2_negate_op(
-; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[TMP2]], 0
-; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i32 [[X]], 0
-; CHECK-NEXT: [[R:%.*]] = and i1 [[NOTZERO]], [[CMP]]
-; CHECK-NEXT: ret i1 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range !0
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i32 [[TMP1]], 1
+; CHECK-NEXT: ret i1 [[TMP2]]
;
%neg = sub i32 0, %x
%and = and i32 %neg, %x
@@ -445,12 +435,9 @@ define i1 @is_pow2_negate_op(i32 %x) {
define <2 x i1> @is_pow2_negate_op_vec(<2 x i32> %x) {
; CHECK-LABEL: @is_pow2_negate_op_vec(
-; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i32> [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i32> [[TMP2]], zeroinitializer
-; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne <2 x i32> [[X]], zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = and <2 x i1> [[CMP]], [[NOTZERO]]
-; CHECK-NEXT: ret <2 x i1> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq <2 x i32> [[TMP1]], <i32 1, i32 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP2]]
;
%neg = sub <2 x i32> zeroinitializer, %x
%and = and <2 x i32> %neg, %x
@@ -496,12 +483,9 @@ define <2 x i1> @is_pow2_decrement_op_ve
define i1 @isnot_pow2_negate_op(i32 %x) {
; CHECK-LABEL: @isnot_pow2_negate_op(
-; CHECK-NEXT: [[TMP1:%.*]] = add i32 [[X:%.*]], -1
-; CHECK-NEXT: [[TMP2:%.*]] = and i32 [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[TMP2]], 0
-; CHECK-NEXT: [[ISZERO:%.*]] = icmp eq i32 [[X]], 0
-; CHECK-NEXT: [[R:%.*]] = or i1 [[CMP]], [[ISZERO]]
-; CHECK-NEXT: ret i1 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X:%.*]]), !range !0
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i32 [[TMP1]], 1
+; CHECK-NEXT: ret i1 [[TMP2]]
;
%neg = sub i32 0, %x
%and = and i32 %neg, %x
@@ -513,12 +497,9 @@ define i1 @isnot_pow2_negate_op(i32 %x)
define <2 x i1> @isnot_pow2_negate_op_vec(<2 x i32> %x) {
; CHECK-LABEL: @isnot_pow2_negate_op_vec(
-; CHECK-NEXT: [[TMP1:%.*]] = add <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT: [[TMP2:%.*]] = and <2 x i32> [[TMP1]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i32> [[TMP2]], zeroinitializer
-; CHECK-NEXT: [[ISZERO:%.*]] = icmp eq <2 x i32> [[X]], zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = or <2 x i1> [[ISZERO]], [[CMP]]
-; CHECK-NEXT: ret <2 x i1> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i32> @llvm.ctpop.v2i32(<2 x i32> [[X:%.*]])
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne <2 x i32> [[TMP1]], <i32 1, i32 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP2]]
;
%neg = sub <2 x i32> zeroinitializer, %x
%and = and <2 x i32> %neg, %x
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