Cleanup of Lowering & LsraInfo

These are preparatory changes for eliminating gtLsraInfo.

Register requirements should never be set on contained nodes. This includes setting isDelayFree and restricting to byte registers for x86.
- This results in net positive diffs for the framework (eliminating incorrect setting of hasDelayFreeSrc), though a net regression for the tests on x86 (including many instances of effectively the same code).
- The regressions are largely related to issue #11274.

Improve consistency of IsValue():
- Any node that can be contained should produce a value, and have a type (e.g. GT_FIELD_LIST).
- Some value nodes (GTK_NOVALUE isn't set) are allowed to have TYP_VOID, in which case IsValue() should return false.
  - This simplifies IsValue().
- Any node that can be assigned a register should return true for IsValue() (e.g. GT_LOCKADD).
- PUTARG_STK doesn't produce a value; get type from its operand.
  - This requires some fixing up of SIMD12 operands.
- Unused GT_LONG nodes shouldn't define any registers

Eliminate isNoRegCompare, by setting type of JTRUE operand to TYP_VOID
  - Set GTF_SET_FLAGS on the operand to ensure it is not eliminated as dead code.

1 files changed, 1 insertions, 8 deletions

diff --git a/src/jit/lsraarmarch.cpp b/src/jit/lsraarmarch.cpp
index 53e223dab6..9351ede35c 100644
--- a/src/jit/lsraarmarch.cpp
+++ b/src/jit/lsraarmarch.cpp
@@ -92,15 +92,8 @@ void LinearScan::TreeNodeInfoInitCmp(GenTreePtr tree)
 {
     TreeNodeInfo* info = &(tree->gtLsraInfo);
 
+    assert((info->dstCount == 1) || (tree->TypeGet() == TYP_VOID));
     info->srcCount = tree->gtOp.gtOp2->isContained() ? 1 : 2;
-    if (info->isNoRegCompare)
-    {
-        info->dstCount = 0;
-    }
-    else
-    {
-        assert((info->dstCount == 1) || tree->OperIs(GT_CMP, GT_TEST_EQ, GT_TEST_NE));
-    }
 }
 
 void LinearScan::TreeNodeInfoInitGCWriteBarrier(GenTree* tree)