Implementation of asm-goto support in LLVM

This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html

This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.

This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.

There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.

Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii

Differential Revision: https://reviews.llvm.org/D53765

llvm-svn: 353563

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 1f40c8f5a4a..4d04e3ff99e 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -921,8 +921,8 @@ Instruction *InstCombiner::foldOpIntoPhi(Instruction &I, PHINode *PN) {
 
     // If the InVal is an invoke at the end of the pred block, then we can't
     // insert a computation after it without breaking the edge.
-    if (InvokeInst *II = dyn_cast<InvokeInst>(InVal))
-      if (II->getParent() == NonConstBB)
+    if (isa<InvokeInst>(InVal))
+      if (cast<Instruction>(InVal)->getParent() == NonConstBB)
         return nullptr;
 
     // If the incoming non-constant value is in I's block, we will remove one