[llvm] r369062 - Move isPointerOffset function to ValueTracking (NFC).
Evgeniy Stepanov via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 15 15:58:28 PDT 2019
Author: eugenis
Date: Thu Aug 15 15:58:28 2019
New Revision: 369062
URL: http://llvm.org/viewvc/llvm-project?rev=369062&view=rev
Log:
Move isPointerOffset function to ValueTracking (NFC).
Summary: To be reused in MemTag sanitizer.
Reviewers: pcc, vitalybuka, ostannard
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D66165
Modified:
llvm/trunk/include/llvm/Analysis/ValueTracking.h
llvm/trunk/lib/Analysis/ValueTracking.cpp
llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
Modified: llvm/trunk/include/llvm/Analysis/ValueTracking.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ValueTracking.h?rev=369062&r1=369061&r2=369062&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ValueTracking.h (original)
+++ llvm/trunk/include/llvm/Analysis/ValueTracking.h Thu Aug 15 15:58:28 2019
@@ -660,6 +660,12 @@ class Value;
Optional<bool> isImpliedByDomCondition(const Value *Cond,
const Instruction *ContextI,
const DataLayout &DL);
+
+ /// Return true if Ptr1 is provably equal to Ptr2 plus a constant offset, and
+ /// return that constant offset. For example, Ptr1 might be &A[42], and Ptr2
+ /// might be &A[40]. In this case offset would be -8.
+ bool isPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset,
+ const DataLayout &DL);
} // end namespace llvm
#endif // LLVM_ANALYSIS_VALUETRACKING_H
Modified: llvm/trunk/lib/Analysis/ValueTracking.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ValueTracking.cpp?rev=369062&r1=369061&r2=369062&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp (original)
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp Thu Aug 15 15:58:28 2019
@@ -5701,3 +5701,86 @@ ConstantRange llvm::computeConstantRange
return CR;
}
+
+static int64_t getOffsetFromIndex(const GEPOperator *GEP, unsigned Idx,
+ bool &VariableIdxFound,
+ const DataLayout &DL) {
+ // Skip over the first indices.
+ gep_type_iterator GTI = gep_type_begin(GEP);
+ for (unsigned i = 1; i != Idx; ++i, ++GTI)
+ /*skip along*/;
+
+ // Compute the offset implied by the rest of the indices.
+ int64_t Offset = 0;
+ for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) {
+ ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i));
+ if (!OpC)
+ return VariableIdxFound = true;
+ if (OpC->isZero())
+ continue; // No offset.
+
+ // Handle struct indices, which add their field offset to the pointer.
+ if (StructType *STy = GTI.getStructTypeOrNull()) {
+ Offset += DL.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
+ continue;
+ }
+
+ // Otherwise, we have a sequential type like an array or vector. Multiply
+ // the index by the ElementSize.
+ uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
+ Offset += Size * OpC->getSExtValue();
+ }
+
+ return Offset;
+}
+
+bool llvm::isPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset,
+ const DataLayout &DL) {
+ Ptr1 = Ptr1->stripPointerCasts();
+ Ptr2 = Ptr2->stripPointerCasts();
+
+ // Handle the trivial case first.
+ if (Ptr1 == Ptr2) {
+ Offset = 0;
+ return true;
+ }
+
+ GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
+ GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
+
+ bool VariableIdxFound = false;
+
+ // If one pointer is a GEP and the other isn't, then see if the GEP is a
+ // constant offset from the base, as in "P" and "gep P, 1".
+ if (GEP1 && !GEP2 && GEP1->getOperand(0)->stripPointerCasts() == Ptr2) {
+ Offset = -getOffsetFromIndex(GEP1, 1, VariableIdxFound, DL);
+ return !VariableIdxFound;
+ }
+
+ if (GEP2 && !GEP1 && GEP2->getOperand(0)->stripPointerCasts() == Ptr1) {
+ Offset = getOffsetFromIndex(GEP2, 1, VariableIdxFound, DL);
+ return !VariableIdxFound;
+ }
+
+ // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical
+ // base. After that base, they may have some number of common (and
+ // potentially variable) indices. After that they handle some constant
+ // offset, which determines their offset from each other. At this point, we
+ // handle no other case.
+ if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0))
+ return false;
+
+ // Skip any common indices and track the GEP types.
+ unsigned Idx = 1;
+ for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx)
+ if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx))
+ break;
+
+ int64_t Offset1 = getOffsetFromIndex(GEP1, Idx, VariableIdxFound, DL);
+ int64_t Offset2 = getOffsetFromIndex(GEP2, Idx, VariableIdxFound, DL);
+ if (VariableIdxFound)
+ return false;
+
+ Offset = Offset2 - Offset1;
+ return true;
+}
Modified: llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp?rev=369062&r1=369061&r2=369062&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/MemCpyOptimizer.cpp Thu Aug 15 15:58:28 2019
@@ -69,90 +69,6 @@ STATISTIC(NumMemSetInfer, "Number of mem
STATISTIC(NumMoveToCpy, "Number of memmoves converted to memcpy");
STATISTIC(NumCpyToSet, "Number of memcpys converted to memset");
-static int64_t GetOffsetFromIndex(const GEPOperator *GEP, unsigned Idx,
- bool &VariableIdxFound,
- const DataLayout &DL) {
- // Skip over the first indices.
- gep_type_iterator GTI = gep_type_begin(GEP);
- for (unsigned i = 1; i != Idx; ++i, ++GTI)
- /*skip along*/;
-
- // Compute the offset implied by the rest of the indices.
- int64_t Offset = 0;
- for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) {
- ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i));
- if (!OpC)
- return VariableIdxFound = true;
- if (OpC->isZero()) continue; // No offset.
-
- // Handle struct indices, which add their field offset to the pointer.
- if (StructType *STy = GTI.getStructTypeOrNull()) {
- Offset += DL.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
- continue;
- }
-
- // Otherwise, we have a sequential type like an array or vector. Multiply
- // the index by the ElementSize.
- uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
- Offset += Size*OpC->getSExtValue();
- }
-
- return Offset;
-}
-
-/// Return true if Ptr1 is provably equal to Ptr2 plus a constant offset, and
-/// return that constant offset. For example, Ptr1 might be &A[42], and Ptr2
-/// might be &A[40]. In this case offset would be -8.
-static bool IsPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset,
- const DataLayout &DL) {
- Ptr1 = Ptr1->stripPointerCasts();
- Ptr2 = Ptr2->stripPointerCasts();
-
- // Handle the trivial case first.
- if (Ptr1 == Ptr2) {
- Offset = 0;
- return true;
- }
-
- GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
- GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
-
- bool VariableIdxFound = false;
-
- // If one pointer is a GEP and the other isn't, then see if the GEP is a
- // constant offset from the base, as in "P" and "gep P, 1".
- if (GEP1 && !GEP2 && GEP1->getOperand(0)->stripPointerCasts() == Ptr2) {
- Offset = -GetOffsetFromIndex(GEP1, 1, VariableIdxFound, DL);
- return !VariableIdxFound;
- }
-
- if (GEP2 && !GEP1 && GEP2->getOperand(0)->stripPointerCasts() == Ptr1) {
- Offset = GetOffsetFromIndex(GEP2, 1, VariableIdxFound, DL);
- return !VariableIdxFound;
- }
-
- // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical
- // base. After that base, they may have some number of common (and
- // potentially variable) indices. After that they handle some constant
- // offset, which determines their offset from each other. At this point, we
- // handle no other case.
- if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0))
- return false;
-
- // Skip any common indices and track the GEP types.
- unsigned Idx = 1;
- for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx)
- if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx))
- break;
-
- int64_t Offset1 = GetOffsetFromIndex(GEP1, Idx, VariableIdxFound, DL);
- int64_t Offset2 = GetOffsetFromIndex(GEP2, Idx, VariableIdxFound, DL);
- if (VariableIdxFound) return false;
-
- Offset = Offset2-Offset1;
- return true;
-}
-
namespace {
/// Represents a range of memset'd bytes with the ByteVal value.
@@ -420,7 +336,7 @@ Instruction *MemCpyOptPass::tryMergingIn
// Check to see if this store is to a constant offset from the start ptr.
int64_t Offset;
- if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset,
+ if (!isPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset,
DL))
break;
@@ -434,7 +350,7 @@ Instruction *MemCpyOptPass::tryMergingIn
// Check to see if this store is to a constant offset from the start ptr.
int64_t Offset;
- if (!IsPointerOffset(StartPtr, MSI->getDest(), Offset, DL))
+ if (!isPointerOffset(StartPtr, MSI->getDest(), Offset, DL))
break;
Ranges.addMemSet(Offset, MSI);
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