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[ConstraintElimination] Fix variables used for pattern matching. 

Re-using the matched variable in the pattern does not work as expected.
This patch fixes that by introducing a new variable for the 2nd level
match.
This commit is contained in:
Florian Hahn 2021-02-14 18:06:09 +00:00
parent f197cf2126
commit 3df5d5aace
2 changed files with 59 additions and 6 deletions
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10
llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
View File

@ -54,20 +54,20 @@ static SmallVector<std::pair<int64_t, Value *>, 4> decompose(Value *V) {
}
auto *GEP = dyn_cast<GetElementPtrInst>(V);
if (GEP && GEP->getNumOperands() == 2 && GEP->isInBounds()) {
Value *Op0;
Value *Op0, *Op1;
ConstantInt *CI;
// If the index is zero-extended, it is guaranteed to be positive.
if (match(GEP->getOperand(GEP->getNumOperands() - 1),
m_ZExt(m_Value(Op0)))) {
if (match(Op0, m_NUWShl(m_Value(Op0), m_ConstantInt(CI))))
if (match(Op0, m_NUWShl(m_Value(Op1), m_ConstantInt(CI))))
return {{0, nullptr},
{1, GEP->getPointerOperand()},
{std::pow(int64_t(2), CI->getSExtValue()), Op0}};
if (match(Op0, m_NSWAdd(m_Value(Op0), m_ConstantInt(CI))))
{std::pow(int64_t(2), CI->getSExtValue()), Op1}};
if (match(Op0, m_NSWAdd(m_Value(Op1), m_ConstantInt(CI))))
return {{CI->getSExtValue(), nullptr},
{1, GEP->getPointerOperand()},
{1, Op0}};
{1, Op1}};
return {{0, nullptr}, {1, GEP->getPointerOperand()}, {1, Op0}};
}

55
llvm/test/Transforms/ConstraintElimination/geps.ll
View File

@ -516,7 +516,7 @@ if.end: ; preds = %entry
}
; Test which requires decomposing GEP %ptr, SHL().
define void @test.ult.gep.shl(i32* readonly %src, i32* readnone %max, i32 %idx, i32 %j) {
define void @test.ult.gep.shl(i32* readonly %src, i32* readnone %max, i32 %idx) {
; CHECK-LABEL: @test.ult.gep.shl(
; CHECK-NEXT: check.0.min:
; CHECK-NEXT: [[ADD_10:%.*]] = getelementptr inbounds i32, i32* [[SRC:%.*]], i32 10
@ -646,4 +646,57 @@ check.max: ; preds = %check.0.min
ret void
}
; Make sure non-constant shift amounts are handled correctly.
define i1 @test.ult.gep.shl.nonconst.zext(i16 %B, i16* readonly %src, i16* readnone %max, i16 %idx, i16 %j) {
; CHECK-LABEL: @test.ult.gep.shl.nonconst.zext(
; CHECK-NEXT: check.0.min:
; CHECK-NEXT: [[ADD_10:%.*]] = getelementptr inbounds i16, i16* [[SRC:%.*]], i16 10
; CHECK-NEXT: [[C_ADD_10_MAX:%.*]] = icmp ugt i16* [[ADD_10]], [[MAX:%.*]]
; CHECK-NEXT: br i1 [[C_ADD_10_MAX]], label [[EXIT_1:%.*]], label [[CHECK_IDX:%.*]]
; CHECK: exit.1:
; CHECK-NEXT: ret i1 true
; CHECK: check.idx:
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i16 [[IDX:%.*]], 5
; CHECK-NEXT: br i1 [[CMP]], label [[CHECK_MAX:%.*]], label [[TRAP:%.*]]
; CHECK: check.max:
; CHECK-NEXT: [[IDX_SHL:%.*]] = shl nuw i16 [[IDX]], [[B:%.*]]
; CHECK-NEXT: [[EXT:%.*]] = zext i16 [[IDX_SHL]] to i64
; CHECK-NEXT: [[ADD_PTR_SHL:%.*]] = getelementptr inbounds i16, i16* [[SRC]], i64 [[EXT]]
; CHECK-NEXT: [[C_MAX:%.*]] = icmp ult i16* [[ADD_PTR_SHL]], [[MAX]]
; CHECK-NEXT: ret i1 [[C_MAX]]
; CHECK: trap:
; CHECK-NEXT: [[IDX_SHL_1:%.*]] = shl nuw i16 [[IDX]], [[B]]
; CHECK-NEXT: [[EXT_1:%.*]] = zext i16 [[IDX_SHL_1]] to i64
; CHECK-NEXT: [[ADD_PTR_SHL_1:%.*]] = getelementptr inbounds i16, i16* [[SRC]], i64 [[EXT_1]]
; CHECK-NEXT: [[C_MAX_1:%.*]] = icmp ult i16* [[ADD_PTR_SHL_1]], [[MAX]]
; CHECK-NEXT: ret i1 [[C_MAX_1]]
;
check.0.min:
%add.10 = getelementptr inbounds i16, i16* %src, i16 10
%c.add.10.max = icmp ugt i16* %add.10, %max
br i1 %c.add.10.max, label %exit.1, label %check.idx
exit.1:
ret i1 true
check.idx: ; preds = %check.0.min
%cmp = icmp ult i16 %idx, 5
br i1 %cmp, label %check.max, label %trap
check.max: ; preds = %check.idx
%idx.shl = shl nuw i16 %idx, %B
%ext = zext i16 %idx.shl to i64
%add.ptr.shl = getelementptr inbounds i16, i16* %src, i64 %ext
%c.max = icmp ult i16* %add.ptr.shl, %max
ret i1 %c.max
trap: ; preds = %check.idx, %check.0.min
%idx.shl.1 = shl nuw i16 %idx, %B
%ext.1 = zext i16 %idx.shl.1 to i64
%add.ptr.shl.1 = getelementptr inbounds i16, i16* %src, i64 %ext.1
%c.max.1 = icmp ult i16* %add.ptr.shl.1, %max
ret i1 %c.max.1
}
declare void @use(i1)