[PATCH] D21690: Fix size computation of array allocation in inline cost analysis

[Easwaran Raman via llvm-commits]

eraman updated this revision to Diff 61858.
eraman added a comment.

Handle overflow in computing stack size.


http://reviews.llvm.org/D21690

Files:
  lib/Analysis/InlineCost.cpp
  test/Transforms/Inline/array-alloca.ll

Index: test/Transforms/Inline/array-alloca.ll
===================================================================
--- /dev/null
+++ test/Transforms/Inline/array-alloca.ll
@@ -0,0 +1,36 @@
+; RUN: opt -inline -S < %s | FileCheck %s
+%struct.A = type { i32 }
+
+define void @callee1(i32 %M) {
+entry:
+  %vla = alloca i32, i32 %M, align 16
+  ret void
+}
+
+define void @callee2(i32 %M) {
+entry:
+  %vla = alloca %struct.A, i32 %M, align 16
+  ret void
+}
+
+define void @callee3(i128 %M) {
+entry:
+  %vla = alloca i32, i128 %M, align 16
+  ret void
+}
+
+; CHECK-LABEL: @caller
+define void @caller() #0 {
+entry:
+  call void @caller()
+; CHECK-NOT: call void @callee1
+  call void @callee1(i32 256)
+; CHECK: call void @callee2
+  call void @callee2(i32 4096)
+; CHECK: call void @callee3
+; This is to test that there is no overflow in computing allocated size
+; call void @callee3(i128 0x8000000000000000);
+  call void @callee3(i128 9223372036854775808);
+  ret void
+}
+
Index: lib/Analysis/InlineCost.cpp
===================================================================
--- lib/Analysis/InlineCost.cpp
+++ lib/Analysis/InlineCost.cpp
@@ -339,9 +339,12 @@
   if (I.isArrayAllocation()) {
     Constant *Size = SimplifiedValues.lookup(I.getArraySize());
     if (auto *AllocSize = dyn_cast_or_null<ConstantInt>(Size)) {
+      const DataLayout &DL = F.getParent()->getDataLayout();
       Type *Ty = I.getAllocatedType();
-      // FIXME: This can't be right. AllocatedSize is in *bytes*.
-      AllocatedSize += Ty->getPrimitiveSizeInBits() * AllocSize->getZExtValue();
+      APInt ArraySize(128, AllocSize->getLimitedValue());
+      APInt ElementSize(128, DL.getTypeAllocSize(Ty));
+      ArraySize *= ElementSize;
+      AllocatedSize += ArraySize.getLimitedValue();
       return Base::visitAlloca(I);
     }
   }


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D21690.61858.patch
Type: text/x-patch
Size: 1830 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20160625/a87643fa/attachment.bin>