[DeadArgElim] Remove allocsize attributes on callsites

We're already removing allocsize attributes from Functions that we
remove args from, since removing arguments from a function may make the
allocsize attribute incorrect. It appears we forgot to also remove them
from callsites.

Without this, I get verifier errors on `@Test2`.

It probably wouldn't be too hard to make DAE properly update allocsize
attributes instead of dropping them, but I can't think of a scenario
where that'd be useful in practice.

llvm-svn: 329868

llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp

@@ -916,8 +916,14 @@ bool DeadArgumentEliminationPass::RemoveDeadStuffFromFunction(Function *F) {
 
     // Reconstruct the AttributesList based on the vector we constructed.
     assert(ArgAttrVec.size() == Args.size());
+
+    // Again, be sure to remove any allocsize attributes, since their indices
+    // may now be incorrect.
+    AttributeSet FnAttrs = CallPAL.getFnAttributes().removeAttribute(
+        F->getContext(), Attribute::AllocSize);
+
     AttributeList NewCallPAL = AttributeList::get(
-        F->getContext(), CallPAL.getFnAttributes(), RetAttrs, ArgAttrVec);
+        F->getContext(), FnAttrs, RetAttrs, ArgAttrVec);
 
     SmallVector<OperandBundleDef, 1> OpBundles;
     CS.getOperandBundlesAsDefs(OpBundles);

llvm/test/Transforms/DeadArgElim/allocsize.ll

@@ -11,3 +11,8 @@ define i64 @NeedsArg(i64 %s) {
 	%c = call i64 @MagickMallocAligned(i64 0, i64 %s)
 	ret i64 %c
 }
+
+define i64 @Test2(i64 %s) {
+	%c = call i64 @MagickMallocAligned(i64 0, i64 %s) allocsize(1)
+	ret i64 %c
+}