Handle vlas during inline cost computation if they'll be turned

into a constant size alloca by inlining.

Ran a run over the testsuite, no results out of the noise, fixes
the testcase in the PR.

PR19115.

llvm-svn: 205710

1 files changed, 10 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/IPA/InlineCost.cpp b/llvm/lib/Analysis/IPA/InlineCost.cpp
index 8dafc1c1c61..a803f8c3bf9 100644
--- a/llvm/lib/Analysis/IPA/InlineCost.cpp
+++ b/llvm/lib/Analysis/IPA/InlineCost.cpp
@@ -287,8 +287,17 @@ bool CallAnalyzer::accumulateGEPOffset(GEPOperator &GEP, APInt &Offset) {
 }
 
 bool CallAnalyzer::visitAlloca(AllocaInst &I) {
-  // FIXME: Check whether inlining will turn a dynamic alloca into a static
+  // Check whether inlining will turn a dynamic alloca into a static
   // alloca, and handle that case.
+  if (I.isArrayAllocation()) {
+    if (Constant *Size = SimplifiedValues.lookup(I.getArraySize())) {
+      ConstantInt *AllocSize = dyn_cast<ConstantInt>(Size);
+      assert(AllocSize && "Allocation size not a constant int?");
+      Type *Ty = I.getAllocatedType();
+      AllocatedSize += Ty->getPrimitiveSizeInBits() * AllocSize->getZExtValue();
+      return Base::visitAlloca(I);
+    }
+  }
 
   // Accumulate the allocated size.
   if (I.isStaticAlloca()) {