[llvm] r317918 - Expand IRBuilder interface for atomic memcpy to require pointer alignments. (NFC)

[Daniel Neilson via llvm-commits]

Author: dneilson
Date: Fri Nov 10 11:38:12 2017
New Revision: 317918

URL: http://llvm.org/viewvc/llvm-project?rev=317918&view=rev
Log:
Expand IRBuilder interface for atomic memcpy to require pointer alignments. (NFC)

Summary:
 The specification of the @llvm.memcpy.element.unordered.atomic intrinsic requires
that the pointer arguments have alignments of at least the element size. The existing
IRBuilder interface to create a call to this intrinsic does not allow for providing
the alignment of these pointer args. Having an interface that makes it easy to
construct invalid intrinsic calls doesn't seem sensible, so this patch simply
adds the requirement that one provide the argument alignments when using IRBuilder
to create atomic memcpy calls.

Modified:
    llvm/trunk/include/llvm/IR/IRBuilder.h
    llvm/trunk/lib/IR/IRBuilder.cpp
    llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

Modified: llvm/trunk/include/llvm/IR/IRBuilder.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/IRBuilder.h?rev=317918&r1=317917&r2=317918&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/IRBuilder.h (original)
+++ llvm/trunk/include/llvm/IR/IRBuilder.h Fri Nov 10 11:38:12 2017
@@ -438,22 +438,26 @@ public:
   /// \brief Create and insert an element unordered-atomic memcpy between the
   /// specified pointers.
   ///
+  /// DstAlign/SrcAlign are the alignments of the Dst/Src pointers, respectively.
+  ///
   /// If the pointers aren't i8*, they will be converted.  If a TBAA tag is
   /// specified, it will be added to the instruction. Likewise with alias.scope
   /// and noalias tags.
   CallInst *CreateElementUnorderedAtomicMemCpy(
-      Value *Dst, Value *Src, uint64_t Size, uint32_t ElementSize,
-      MDNode *TBAATag = nullptr, MDNode *TBAAStructTag = nullptr,
-      MDNode *ScopeTag = nullptr, MDNode *NoAliasTag = nullptr) {
+      Value *Dst, unsigned DstAlign, Value *Src, unsigned SrcAlign,
+      uint64_t Size, uint32_t ElementSize, MDNode *TBAATag = nullptr,
+      MDNode *TBAAStructTag = nullptr, MDNode *ScopeTag = nullptr,
+      MDNode *NoAliasTag = nullptr) {
     return CreateElementUnorderedAtomicMemCpy(
-        Dst, Src, getInt64(Size), ElementSize, TBAATag, TBAAStructTag, ScopeTag,
-        NoAliasTag);
+        Dst, DstAlign, Src, SrcAlign, getInt64(Size), ElementSize, TBAATag,
+        TBAAStructTag, ScopeTag, NoAliasTag);
   }
 
   CallInst *CreateElementUnorderedAtomicMemCpy(
-      Value *Dst, Value *Src, Value *Size, uint32_t ElementSize,
-      MDNode *TBAATag = nullptr, MDNode *TBAAStructTag = nullptr,
-      MDNode *ScopeTag = nullptr, MDNode *NoAliasTag = nullptr);
+      Value *Dst, unsigned DstAlign, Value *Src, unsigned SrcAlign, Value *Size,
+      uint32_t ElementSize, MDNode *TBAATag = nullptr,
+      MDNode *TBAAStructTag = nullptr, MDNode *ScopeTag = nullptr,
+      MDNode *NoAliasTag = nullptr);
 
   /// \brief Create and insert a memmove between the specified
   /// pointers.

Modified: llvm/trunk/lib/IR/IRBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/IRBuilder.cpp?rev=317918&r1=317917&r2=317918&view=diff
==============================================================================
--- llvm/trunk/lib/IR/IRBuilder.cpp (original)
+++ llvm/trunk/lib/IR/IRBuilder.cpp Fri Nov 10 11:38:12 2017
@@ -135,8 +135,13 @@ CreateMemCpy(Value *Dst, Value *Src, Val
 }
 
 CallInst *IRBuilderBase::CreateElementUnorderedAtomicMemCpy(
-    Value *Dst, Value *Src, Value *Size, uint32_t ElementSize, MDNode *TBAATag,
-    MDNode *TBAAStructTag, MDNode *ScopeTag, MDNode *NoAliasTag) {
+    Value *Dst, unsigned DstAlign, Value *Src, unsigned SrcAlign, Value *Size,
+    uint32_t ElementSize, MDNode *TBAATag, MDNode *TBAAStructTag,
+    MDNode *ScopeTag, MDNode *NoAliasTag) {
+  assert(DstAlign >= ElementSize &&
+         "Pointer alignment must be at least element size");
+  assert(SrcAlign >= ElementSize &&
+         "Pointer alignment must be at least element size");
   Dst = getCastedInt8PtrValue(Dst);
   Src = getCastedInt8PtrValue(Src);
 
@@ -148,6 +153,10 @@ CallInst *IRBuilderBase::CreateElementUn
 
   CallInst *CI = createCallHelper(TheFn, Ops, this);
 
+  // Set the alignment of the pointer args.
+  CI->addParamAttr(0, Attribute::getWithAlignment(CI->getContext(), DstAlign));
+  CI->addParamAttr(1, Attribute::getWithAlignment(CI->getContext(), SrcAlign));
+
   // Set the TBAA info if present.
   if (TBAATag)
     CI->setMetadata(LLVMContext::MD_tbaa, TBAATag);

Modified: llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp?rev=317918&r1=317917&r2=317918&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp Fri Nov 10 11:38:12 2017
@@ -1063,16 +1063,12 @@ bool LoopIdiomRecognize::processLoopStor
     if (StoreSize > TTI->getAtomicMemIntrinsicMaxElementSize())
       return false;
 
+    // Create the call.
+    // Note that unordered atomic loads/stores are *required* by the spec to
+    // have an alignment but non-atomic loads/stores may not.
     NewCall = Builder.CreateElementUnorderedAtomicMemCpy(
-        StoreBasePtr, LoadBasePtr, NumBytes, StoreSize);
-
-    // Propagate alignment info onto the pointer args. Note that unordered
-    // atomic loads/stores are *required* by the spec to have an alignment
-    // but non-atomic loads/stores may not.
-    NewCall->addParamAttr(0, Attribute::getWithAlignment(NewCall->getContext(),
-                                                         SI->getAlignment()));
-    NewCall->addParamAttr(1, Attribute::getWithAlignment(NewCall->getContext(),
-                                                         LI->getAlignment()));
+        StoreBasePtr, SI->getAlignment(), LoadBasePtr, LI->getAlignment(),
+        NumBytes, StoreSize);
   }
   NewCall->setDebugLoc(SI->getDebugLoc());