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[InstCombine] foldICmpWithLowBitMaskedVal(): handle uncanonical ((-1 …
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…<< y) >> y) mask

Summary:
The last low-bit-mask-pattern-producing-pattern i can think of.

https://rise4fun.com/Alive/UGzE <- non-canonical
But we can not canonicalize it because of extra uses.

https://bugs.llvm.org/show_bug.cgi?id=38123

Reviewers: spatel, craig.topper, RKSimon

Reviewed By: spatel

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D52148

llvm-svn: 342548
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@LebedevRI
LebedevRI committed Sep 19, 2018
1 parent ca2bdb0 commit f50023d
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Showing 3 changed files with 43 additions and 55 deletions.
12 changes: 7 additions & 5 deletions llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
View file
Expand Up @@ -2886,6 +2886,7 @@ Instruction *InstCombiner::foldICmpInstWithConstantNotInt(ICmpInst &I) {
/// icmp SrcPred (x & Mask), x to icmp DstPred x, Mask
/// Where Mask is some pattern that produces all-ones in low bits:
/// (-1 >> y)
/// ((-1 << y) >> y) <- non-canonical, has extra uses
/// ~(-1 << y)
/// ((1 << y) + (-1)) <- non-canonical, has extra uses
/// The Mask can be a constant, too.
Expand All @@ -2894,11 +2895,12 @@ Instruction *InstCombiner::foldICmpInstWithConstantNotInt(ICmpInst &I) {
static Value *foldICmpWithLowBitMaskedVal(ICmpInst &I,
InstCombiner::BuilderTy &Builder) {
ICmpInst::Predicate SrcPred;
Value *X, *M;
auto m_VariableMask =
m_CombineOr(m_CombineOr(m_Not(m_Shl(m_AllOnes(), m_Value())),
m_Add(m_Shl(m_One(), m_Value()), m_AllOnes())),
m_LShr(m_AllOnes(), m_Value()));
Value *X, *M, *Y;
auto m_VariableMask = m_CombineOr(
m_CombineOr(m_Not(m_Shl(m_AllOnes(), m_Value())),
m_Add(m_Shl(m_One(), m_Value()), m_AllOnes())),
m_CombineOr(m_LShr(m_AllOnes(), m_Value()),
m_LShr(m_Shl(m_AllOnes(), m_Value(Y)), m_Deferred(Y))));
auto m_Mask = m_CombineOr(m_VariableMask, m_LowBitMask());
if (!match(&I, m_c_ICmp(SrcPred,
m_c_And(m_CombineAnd(m_Mask, m_Value(M)), m_Value(X)),
Expand Down
43 changes: 18 additions & 25 deletions llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v4-and-icmp-eq-to-icmp-ule.ll
View file
Expand Up @@ -23,9 +23,8 @@ define i1 @p0(i8 %x, i8 %y) {
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -44,9 +43,8 @@ define <2 x i1> @p1_vec(<2 x i8> %x, <2 x i8> %y) {
; CHECK-NEXT: [[T0:%.*]] = shl <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: call void @use2i8(<2 x i8> [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr <2 x i8> [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and <2 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq <2 x i8> [[T2]], [[X]]
; CHECK-NEXT: ret <2 x i1> [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge <2 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%t0 = shl <2 x i8> <i8 -1, i8 -1>, %y
call void @use2i8(<2 x i8> %t0)
Expand All @@ -61,9 +59,8 @@ define <3 x i1> @p2_vec_undef0(<3 x i8> %x, <3 x i8> %y) {
; CHECK-NEXT: [[T0:%.*]] = shl <3 x i8> <i8 -1, i8 undef, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: call void @use3i8(<3 x i8> [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr <3 x i8> [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and <3 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq <3 x i8> [[T2]], [[X]]
; CHECK-NEXT: ret <3 x i1> [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge <3 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: ret <3 x i1> [[TMP1]]
;
%t0 = shl <3 x i8> <i8 -1, i8 undef, i8 -1>, %y
call void @use3i8(<3 x i8> %t0)
Expand All @@ -85,9 +82,8 @@ define i1 @c0(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[X]], [[T1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ule i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -104,9 +100,8 @@ define i1 @c1(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[X]], [[T2]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ule i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -123,9 +118,8 @@ define i1 @c2(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[X]], [[T1]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[X]], [[T2]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ule i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -146,9 +140,8 @@ define i1 @oneuse0(i8 %x, i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0) ; needed anyway
Expand All @@ -166,8 +159,8 @@ define i1 @oneuse1(i8 %x, i8 %y) {
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge i8 [[T1]], [[X]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0) ; needed anyway
Expand All @@ -186,8 +179,8 @@ define i1 @oneuse2(i8 %x, i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
; CHECK-NEXT: [[RET:%.*]] = icmp eq i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp uge i8 [[T1]], [[X]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand Down
43 changes: 18 additions & 25 deletions llvm/test/Transforms/InstCombine/canonicalize-low-bit-mask-v4-and-icmp-ne-to-icmp-ugt.ll
View file
Expand Up @@ -23,9 +23,8 @@ define i1 @p0(i8 %x, i8 %y) {
; CHECK-NEXT: [[T0:%.*]] = shl i8 -1, [[Y:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -44,9 +43,8 @@ define <2 x i1> @p1_vec(<2 x i8> %x, <2 x i8> %y) {
; CHECK-NEXT: [[T0:%.*]] = shl <2 x i8> <i8 -1, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: call void @use2i8(<2 x i8> [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr <2 x i8> [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and <2 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne <2 x i8> [[T2]], [[X]]
; CHECK-NEXT: ret <2 x i1> [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <2 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: ret <2 x i1> [[TMP1]]
;
%t0 = shl <2 x i8> <i8 -1, i8 -1>, %y
call void @use2i8(<2 x i8> %t0)
Expand All @@ -61,9 +59,8 @@ define <3 x i1> @p2_vec_undef0(<3 x i8> %x, <3 x i8> %y) {
; CHECK-NEXT: [[T0:%.*]] = shl <3 x i8> <i8 -1, i8 undef, i8 -1>, [[Y:%.*]]
; CHECK-NEXT: call void @use3i8(<3 x i8> [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr <3 x i8> [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and <3 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne <3 x i8> [[T2]], [[X]]
; CHECK-NEXT: ret <3 x i1> [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult <3 x i8> [[T1]], [[X:%.*]]
; CHECK-NEXT: ret <3 x i1> [[TMP1]]
;
%t0 = shl <3 x i8> <i8 -1, i8 undef, i8 -1>, %y
call void @use3i8(<3 x i8> %t0)
Expand All @@ -85,9 +82,8 @@ define i1 @c0(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[X]], [[T1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -104,9 +100,8 @@ define i1 @c1(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[X]], [[T2]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -123,9 +118,8 @@ define i1 @c2(i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[X:%.*]] = call i8 @gen8()
; CHECK-NEXT: [[T2:%.*]] = and i8 [[X]], [[T1]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[X]], [[T2]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ugt i8 [[X]], [[T1]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand All @@ -146,9 +140,8 @@ define i1 @oneuse0(i8 %x, i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T0]])
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0) ; needed anyway
Expand All @@ -166,8 +159,8 @@ define i1 @oneuse1(i8 %x, i8 %y) {
; CHECK-NEXT: [[T1:%.*]] = lshr i8 [[T0]], [[Y]]
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i8 [[T1]], [[X]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0) ; needed anyway
Expand All @@ -186,8 +179,8 @@ define i1 @oneuse2(i8 %x, i8 %y) {
; CHECK-NEXT: call void @use8(i8 [[T1]])
; CHECK-NEXT: [[T2:%.*]] = and i8 [[T1]], [[X:%.*]]
; CHECK-NEXT: call void @use8(i8 [[T2]])
; CHECK-NEXT: [[RET:%.*]] = icmp ne i8 [[T2]], [[X]]
; CHECK-NEXT: ret i1 [[RET]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp ult i8 [[T1]], [[X]]
; CHECK-NEXT: ret i1 [[TMP1]]
;
%t0 = shl i8 -1, %y
call void @use8(i8 %t0)
Expand Down

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