commit fd72bf21c958ae2fdfaa8654df55367c72575d3a
author Florian Hahn <flo@fhahn.com> Thu Aug 15 12:13:02 2019 +0000
committer Florian Hahn <flo@fhahn.com> Thu Aug 15 12:13:02 2019 +0000
tree ac93587b37c3784be4ef3f8b977517e67fc2edfd
parent 5e9a16408ced992d7e2ac6f0acf2b9a1ee0dd862

[ValueTracking] Add MustPreserveNullness arg to functions analyzing calls. (NFC)

Some uses of getArgumentAliasingToReturnedPointer and
isIntrinsicReturningPointerAliasingArgumentWithoutCapturing require the
calls/intrinsics to preserve the nullness of the argument.

For alias analysis, the nullness property does not really come into
play.

This patch explicitly sets it to true. In D61669, the alias analysis
uses will be switched to not require preserving nullness.

Reviewers: nlopes, efriedma, hfinkel, sanjoy, aqjune, jdoerfert

Reviewed By: jdoerfert

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64150

llvm-svn: 368993

llvm/lib/Analysis/BasicAliasAnalysis.cpp

diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 3721c99..ef57173 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -481,7 +481,7 @@
         // because it should be in sync with CaptureTracking. Not using it may
         // cause weird miscompilations where 2 aliasing pointers are assumed to
         // noalias.
-        if (auto *RP = getArgumentAliasingToReturnedPointer(Call)) {
+        if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true)) {
           V = RP;
           continue;
         }

llvm/lib/Analysis/CaptureTracking.cpp

diff --git a/llvm/lib/Analysis/CaptureTracking.cpp b/llvm/lib/Analysis/CaptureTracking.cpp
index adaa83a..f12e50e 100644
--- a/llvm/lib/Analysis/CaptureTracking.cpp
+++ b/llvm/lib/Analysis/CaptureTracking.cpp
@@ -251,7 +251,8 @@
       // marked with nocapture do not capture. This means that places like
       // GetUnderlyingObject in ValueTracking or DecomposeGEPExpression
       // in BasicAA also need to know about this property.
-      if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call)) {
+      if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call,
+                                                                      true)) {
         AddUses(Call);
         break;
       }

llvm/lib/Analysis/Loads.cpp

diff --git a/llvm/lib/Analysis/Loads.cpp b/llvm/lib/Analysis/Loads.cpp
index 31da4e9..33db7fb 100644
--- a/llvm/lib/Analysis/Loads.cpp
+++ b/llvm/lib/Analysis/Loads.cpp
@@ -107,7 +107,7 @@
                                               DL, CtxI, DT, Visited);
 
   if (const auto *Call = dyn_cast<CallBase>(V))
-    if (auto *RP = getArgumentAliasingToReturnedPointer(Call))
+    if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
       return isDereferenceableAndAlignedPointer(RP, Align, Size, DL, CtxI, DT,
                                                 Visited);
 

llvm/lib/Analysis/ValueTracking.cpp

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 2773b60..74c813f 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -2073,7 +2073,7 @@
     if (const auto *Call = dyn_cast<CallBase>(V)) {
       if (Call->isReturnNonNull())
         return true;
-      if (const auto *RP = getArgumentAliasingToReturnedPointer(Call))
+      if (const auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
         return isKnownNonZero(RP, Depth, Q);
     }
   }
@@ -3658,19 +3658,22 @@
   return Len == ~0ULL ? 1 : Len;
 }
 
-const Value *llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call) {
+const Value *
+llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call,
+                                           bool MustPreserveNullness) {
   assert(Call &&
          "getArgumentAliasingToReturnedPointer only works on nonnull calls");
   if (const Value *RV = Call->getReturnedArgOperand())
     return RV;
   // This can be used only as a aliasing property.
-  if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(Call))
+  if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
+          Call, MustPreserveNullness))
     return Call->getArgOperand(0);
   return nullptr;
 }
 
 bool llvm::isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
-    const CallBase *Call) {
+    const CallBase *Call, bool MustPreserveNullness) {
   return Call->getIntrinsicID() == Intrinsic::launder_invariant_group ||
          Call->getIntrinsicID() == Intrinsic::strip_invariant_group ||
          Call->getIntrinsicID() == Intrinsic::aarch64_irg ||
@@ -3732,7 +3735,7 @@
         // because it should be in sync with CaptureTracking. Not using it may
         // cause weird miscompilations where 2 aliasing pointers are assumed to
         // noalias.
-        if (auto *RP = getArgumentAliasingToReturnedPointer(Call)) {
+        if (auto *RP = getArgumentAliasingToReturnedPointer(Call, true)) {
           V = RP;
           continue;
         }