[WebAssembly] Implement eliminateCallFramePseudo

Summary:
Implement eliminateCallFramePsuedo to handle ADJCALLSTACKUP/DOWN
pseudo-instructions. Add a test calling a vararg function which causes non-0
adjustments. This revealed an issue with RegisterCoalescer wherein it
eliminates a COPY from SP32 to a vreg but failes to update the live ranges
of EXPR_STACK, causing a machineinstr verifier failure (so this test
is commented out).

Also add a dynamic alloca test, which causes a callseq_end dag node with
a 0 (instead of undef) second argument to be generated. We currently fail to
select that, so adjust the ADJCALLSTACKUP tablegen code to handle it.

Differential Revision: http://reviews.llvm.org/D15587

llvm-svn: 255844

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 597d6f4..2364366 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -445,7 +445,7 @@ WebAssemblyTargetLowering::LowerCall(CallLoweringInfo &CLI,
   }
 
   if (NumBytes) {
-    SDValue Unused = DAG.getUNDEF(PtrVT);
+    SDValue Unused = DAG.getTargetConstant(0, DL, PtrVT);
     Chain = DAG.getCALLSEQ_END(Chain, NB, Unused, SDValue(), DL);
   }