[llvm] r364856 - [InstCombine] reduce more checks for power-of-2-or-zero using ctpop
Sanjay Patel via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 1 15:00:00 PDT 2019
Author: spatel
Date: Mon Jul 1 15:00:00 2019
New Revision: 364856
URL: http://llvm.org/viewvc/llvm-project?rev=364856&view=rev
Log:
[InstCombine] reduce more checks for power-of-2-or-zero using ctpop
Extends the transform from:
rL364341
...to include another (more common?) pattern that tests whether a
value is a power-of-2 (including or excluding zero).
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=364856&r1=364855&r2=364856&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCompares.cpp Mon Jul 1 15:00:00 2019
@@ -3926,9 +3926,15 @@ Instruction *InstCombiner::foldICmpEqual
return new ICmpInst(Pred, A, B);
// Canonicalize checking for a power-of-2-or-zero value:
+ // (A & (A-1)) == 0 --> ctpop(A) < 2 (two commuted variants)
+ // ((A-1) & A) != 0 --> ctpop(A) > 1 (two commuted variants)
+ if (!match(Op0, m_OneUse(m_c_And(m_Add(m_Value(A), m_AllOnes()),
+ m_Deferred(A)))) ||
+ !match(Op1, m_ZeroInt()))
+ A = nullptr;
+
// (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_Neg(m_Specific(Op1)), m_Specific(Op1)))))
A = Op1;
else if (match(Op1,
Modified: llvm/trunk/test/Transforms/InstCombine/ispow2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/ispow2.ll?rev=364856&r1=364855&r2=364856&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/ispow2.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/ispow2.ll Mon Jul 1 15:00:00 2019
@@ -27,9 +27,8 @@ define <2 x i1> @is_pow2or0_negate_op_ve
define i1 @is_pow2or0_decrement_op(i8 %x) {
; CHECK-LABEL: @is_pow2or0_decrement_op(
-; CHECK-NEXT: [[DEC:%.*]] = add i8 [[X:%.*]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i8 [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[AND]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i8 @llvm.ctpop.i8(i8 [[X:%.*]]), !range !1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[TMP1]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
%dec = add i8 %x, -1
@@ -40,9 +39,8 @@ define i1 @is_pow2or0_decrement_op(i8 %x
define <2 x i1> @is_pow2or0_decrement_op_vec(<2 x i8> %x) {
; CHECK-LABEL: @is_pow2or0_decrement_op_vec(
-; CHECK-NEXT: [[DEC:%.*]] = add <2 x i8> [[X:%.*]], <i8 -1, i8 -1>
-; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i8> [[AND]], zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> [[X:%.*]])
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult <2 x i8> [[TMP1]], <i8 2, i8 2>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%dec = add <2 x i8> %x, <i8 -1, i8 -1>
@@ -77,9 +75,8 @@ define <2 x i1> @isnot_pow2or0_negate_op
define i1 @isnot_pow2or0_decrement_op(i8 %x) {
; CHECK-LABEL: @isnot_pow2or0_decrement_op(
-; CHECK-NEXT: [[DEC:%.*]] = add i8 [[X:%.*]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i8 [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[AND]], 0
+; CHECK-NEXT: [[TMP1:%.*]] = call i8 @llvm.ctpop.i8(i8 [[X:%.*]]), !range !1
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
%dec = add i8 %x, -1
@@ -90,9 +87,8 @@ define i1 @isnot_pow2or0_decrement_op(i8
define <2 x i1> @isnot_pow2or0_decrement_op_vec(<2 x i8> %x) {
; CHECK-LABEL: @isnot_pow2or0_decrement_op_vec(
-; CHECK-NEXT: [[DEC:%.*]] = add <2 x i8> [[X:%.*]], <i8 -1, i8 -1>
-; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i8> [[AND]], zeroinitializer
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> [[X:%.*]])
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt <2 x i8> [[TMP1]], <i8 1, i8 1>
; CHECK-NEXT: ret <2 x i1> [[CMP]]
;
%dec = add <2 x i8> %x, <i8 -1, i8 -1>
@@ -104,7 +100,7 @@ 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:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !1
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !2
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[TMP1]], 2
; CHECK-NEXT: ret i1 [[CMP]]
;
@@ -120,7 +116,7 @@ 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:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !2
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !3
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
@@ -134,7 +130,7 @@ 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:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !2
+; CHECK-NEXT: [[TMP1:%.*]] = call i32 @llvm.ctpop.i32(i32 [[X]]), !range !3
; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[TMP1]], 1
; CHECK-NEXT: ret i1 [[CMP]]
;
@@ -449,12 +445,9 @@ define <2 x i1> @is_pow2_negate_op_vec(<
define i1 @is_pow2_decrement_op(i8 %x) {
; CHECK-LABEL: @is_pow2_decrement_op(
-; CHECK-NEXT: [[DEC:%.*]] = add i8 [[X:%.*]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i8 [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq i8 [[AND]], 0
-; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne i8 [[X]], 0
-; CHECK-NEXT: [[R:%.*]] = and i1 [[CMP]], [[NOTZERO]]
-; CHECK-NEXT: ret i1 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call i8 @llvm.ctpop.i8(i8 [[X:%.*]]), !range !1
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq i8 [[TMP1]], 1
+; CHECK-NEXT: ret i1 [[TMP2]]
;
%dec = add i8 %x, -1
%and = and i8 %dec, %x
@@ -466,12 +459,9 @@ define i1 @is_pow2_decrement_op(i8 %x) {
define <2 x i1> @is_pow2_decrement_op_vec(<2 x i8> %x) {
; CHECK-LABEL: @is_pow2_decrement_op_vec(
-; CHECK-NEXT: [[DEC:%.*]] = add <2 x i8> [[X:%.*]], <i8 -1, i8 -1>
-; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp eq <2 x i8> [[AND]], zeroinitializer
-; CHECK-NEXT: [[NOTZERO:%.*]] = icmp ne <2 x i8> [[X]], zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = and <2 x i1> [[NOTZERO]], [[CMP]]
-; CHECK-NEXT: ret <2 x i1> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> [[X:%.*]])
+; CHECK-NEXT: [[TMP2:%.*]] = icmp eq <2 x i8> [[TMP1]], <i8 1, i8 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP2]]
;
%dec = add <2 x i8> %x, <i8 -1, i8 -1>
%and = and <2 x i8> %dec, %x
@@ -511,12 +501,9 @@ define <2 x i1> @isnot_pow2_negate_op_ve
define i1 @isnot_pow2_decrement_op(i8 %x) {
; CHECK-LABEL: @isnot_pow2_decrement_op(
-; CHECK-NEXT: [[DEC:%.*]] = add i8 [[X:%.*]], -1
-; CHECK-NEXT: [[AND:%.*]] = and i8 [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne i8 [[AND]], 0
-; CHECK-NEXT: [[ISZERO:%.*]] = icmp eq i8 [[X]], 0
-; CHECK-NEXT: [[R:%.*]] = or i1 [[ISZERO]], [[CMP]]
-; CHECK-NEXT: ret i1 [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call i8 @llvm.ctpop.i8(i8 [[X:%.*]]), !range !1
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne i8 [[TMP1]], 1
+; CHECK-NEXT: ret i1 [[TMP2]]
;
%dec = add i8 %x, -1
%and = and i8 %dec, %x
@@ -528,12 +515,9 @@ define i1 @isnot_pow2_decrement_op(i8 %x
define <2 x i1> @isnot_pow2_decrement_op_vec(<2 x i8> %x) {
; CHECK-LABEL: @isnot_pow2_decrement_op_vec(
-; CHECK-NEXT: [[DEC:%.*]] = add <2 x i8> [[X:%.*]], <i8 -1, i8 -1>
-; CHECK-NEXT: [[AND:%.*]] = and <2 x i8> [[DEC]], [[X]]
-; CHECK-NEXT: [[CMP:%.*]] = icmp ne <2 x i8> [[AND]], zeroinitializer
-; CHECK-NEXT: [[ISZERO:%.*]] = icmp eq <2 x i8> [[X]], zeroinitializer
-; CHECK-NEXT: [[R:%.*]] = or <2 x i1> [[CMP]], [[ISZERO]]
-; CHECK-NEXT: ret <2 x i1> [[R]]
+; CHECK-NEXT: [[TMP1:%.*]] = call <2 x i8> @llvm.ctpop.v2i8(<2 x i8> [[X:%.*]])
+; CHECK-NEXT: [[TMP2:%.*]] = icmp ne <2 x i8> [[TMP1]], <i8 1, i8 1>
+; CHECK-NEXT: ret <2 x i1> [[TMP2]]
;
%dec = add <2 x i8> %x, <i8 -1, i8 -1>
%and = and <2 x i8> %dec, %x
More information about the llvm-commits
mailing list