[llvm] r290905 - [CodeGen] Simplify logic that looks for returned call operands. NFC-ish.

[Ahmed Bougacha via llvm-commits]

Author: ab
Date: Tue Jan  3 14:33:22 2017
New Revision: 290905

URL: http://llvm.org/viewvc/llvm-project?rev=290905&view=rev
Log:
[CodeGen] Simplify logic that looks for returned call operands. NFC-ish.

Use getReturnedArgOperand() instead of rolling our own.  Note that it's
equivalent because there can only be one 'returned' operand.

The existing code was also incorrect: there already was awkward logic to
ignore callee/EH blocks, but operands can now also be operand bundles,
in which case we'll look for non-existent parameter attributes.

Unfortunately, this isn't observable in-tree, as it only crashes when
exercising the regular call lowering logic with operand bundles.
Still, this is a nice small cleanup anyway.

Modified:
    llvm/trunk/lib/CodeGen/Analysis.cpp

Modified: llvm/trunk/lib/CodeGen/Analysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/Analysis.cpp?rev=290905&r1=290904&r2=290905&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/Analysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/Analysis.cpp Tue Jan  3 14:33:22 2017
@@ -272,28 +272,16 @@ static const Value *getNoopInput(const V
                TLI.allowTruncateForTailCall(Op->getType(), I->getType())) {
       DataBits = std::min(DataBits, I->getType()->getPrimitiveSizeInBits());
       NoopInput = Op;
-    } else if (isa<CallInst>(I)) {
-      // Look through call (skipping callee)
-      for (User::const_op_iterator i = I->op_begin(), e = I->op_end() - 1;
-           i != e; ++i) {
-        unsigned attrInd = i - I->op_begin() + 1;
-        if (cast<CallInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
-            isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
-          NoopInput = *i;
-          break;
-        }
-      }
-    } else if (isa<InvokeInst>(I)) {
-      // Look through invoke (skipping BB, BB, Callee)
-      for (User::const_op_iterator i = I->op_begin(), e = I->op_end() - 3;
-           i != e; ++i) {
-        unsigned attrInd = i - I->op_begin() + 1;
-        if (cast<InvokeInst>(I)->paramHasAttr(attrInd, Attribute::Returned) &&
-            isNoopBitcast((*i)->getType(), I->getType(), TLI)) {
-          NoopInput = *i;
-          break;
-        }
-      }
+    } else if (auto *CI = dyn_cast<CallInst>(I)) {
+      // Look through call operands.
+      Value *ReturnedOp = CI->getReturnedArgOperand();
+      if (ReturnedOp && isNoopBitcast(ReturnedOp->getType(), I->getType(), TLI))
+        NoopInput = ReturnedOp;
+    } else if (auto *II = dyn_cast<InvokeInst>(I)) {
+      // Look through invoke operands.
+      Value *ReturnedOp = II->getReturnedArgOperand();
+      if (ReturnedOp && isNoopBitcast(ReturnedOp->getType(), I->getType(), TLI))
+        NoopInput = ReturnedOp;
     } else if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(V)) {
       // Value may come from either the aggregate or the scalar
       ArrayRef<unsigned> InsertLoc = IVI->getIndices();