[PATCH] Add an inalloca flag to allocas

[Reid Kleckner]

  Thanks!


================
Comment at: docs/LangRef.rst:734
@@ +733,3 @@
+    The alloca, or argument allocation, must also be tagged with the
+    inalloca keyword.  Only the past argument may have the ``inalloca``
+    attribute, and that argument is guaranteed to be passed in memory.
----------------
David Majnemer wrote:
> Should "past" be "last" instead?
woops, yeah.

================
Comment at: include/llvm/IR/Instructions.h:104
@@ -103,3 +103,3 @@
   unsigned getAlignment() const {
-    return (1u << getSubclassDataFromInstruction()) >> 1;
+    return (1u << (getSubclassDataFromInstruction() & 31)) >> 1;
   }
----------------
David Majnemer wrote:
> This is fine because we don't support alignments larger than 536870912 (which would leave us with bits 30 and 31 free).
> 
> I would have an assert relating with Value::MaximumAlignment.
There's an assert in setAlignment that it round trips after masking and shifting, so I'm happy with that.


http://llvm-reviews.chandlerc.com/D2571

BRANCH
  inalloca

ARCANIST PROJECT
  llvm