Update optimization passes to handle inalloca arguments

Summary:
I searched Transforms/ and Analysis/ for 'ByVal' and updated those call
sites to check for inalloca if appropriate.

I added tests for any change that would allow an optimization to fire on
inalloca.

Reviewers: nlewycky

Differential Revision: http://llvm-reviews.chandlerc.com/D2449

llvm-svn: 200281

2 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 7d2fc0a5289..8e308ecacf3 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -767,10 +767,10 @@ static bool isSafeToEliminateVarargsCast(const CallSite CS,
   if (!CI->isLosslessCast())
     return false;
 
-  // The size of ByVal arguments is derived from the type, so we
+  // The size of ByVal or InAlloca arguments is derived from the type, so we
   // can't change to a type with a different size.  If the size were
   // passed explicitly we could avoid this check.
-  if (!CS.isByValArgument(ix))
+  if (!CS.isByValOrInAllocaArgument(ix))
     return true;
 
   Type* SrcTy =
@@ -1049,6 +1049,9 @@ bool InstCombiner::transformConstExprCastCall(CallSite CS) {
                         typeIncompatible(ParamTy, i + 1), i + 1))
       return false;   // Attribute not compatible with transformed value.
 
+    if (CS.isInAllocaArgument(i))
+      return false;   // Cannot transform to and from inalloca.
+
     // If the parameter is passed as a byval argument, then we have to have a
     // sized type and the sized type has to have the same size as the old type.
     if (ParamTy != ActTy &&
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index 4c861b3fd09..1f691768177 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -81,10 +81,14 @@ isOnlyCopiedFromConstantGlobal(Value *V, MemTransferInst *&TheCopy,
       if (CS.isCallee(UI))
         continue;
 
+      // Inalloca arguments are clobbered by the call.
+      unsigned ArgNo = CS.getArgumentNo(UI);
+      if (CS.isInAllocaArgument(ArgNo))
+        return false;
+
       // If this is a readonly/readnone call site, then we know it is just a
       // load (but one that potentially returns the value itself), so we can
       // ignore it if we know that the value isn't captured.
-      unsigned ArgNo = CS.getArgumentNo(UI);
       if (CS.onlyReadsMemory() &&
           (CS.getInstruction()->use_empty() || CS.doesNotCapture(ArgNo)))
         continue;