[llvm] r273952 - Fix size computation of array allocation in inline cost analysis

[Easwaran Raman via llvm-commits]

Author: eraman
Date: Mon Jun 27 17:31:53 2016
New Revision: 273952

URL: http://llvm.org/viewvc/llvm-project?rev=273952&view=rev
Log:
Fix size computation of array allocation in inline cost analysis

Differential revision: http://reviews.llvm.org/D21690


Added:
    llvm/trunk/test/Transforms/Inline/array-alloca.ll
Modified:
    llvm/trunk/lib/Analysis/InlineCost.cpp

Modified: llvm/trunk/lib/Analysis/InlineCost.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/InlineCost.cpp?rev=273952&r1=273951&r2=273952&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/InlineCost.cpp (original)
+++ llvm/trunk/lib/Analysis/InlineCost.cpp Mon Jun 27 17:31:53 2016
@@ -339,9 +339,10 @@ bool CallAnalyzer::visitAlloca(AllocaIns
   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();
+      AllocatedSize = SaturatingMultiplyAdd(
+          AllocSize->getLimitedValue(), DL.getTypeAllocSize(Ty), AllocatedSize);
       return Base::visitAlloca(I);
     }
   }
@@ -350,7 +351,7 @@ bool CallAnalyzer::visitAlloca(AllocaIns
   if (I.isStaticAlloca()) {
     const DataLayout &DL = F.getParent()->getDataLayout();
     Type *Ty = I.getAllocatedType();
-    AllocatedSize += DL.getTypeAllocSize(Ty);
+    AllocatedSize = SaturatingAdd(DL.getTypeAllocSize(Ty), AllocatedSize);
   }
 
   // We will happily inline static alloca instructions.

Added: llvm/trunk/test/Transforms/Inline/array-alloca.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Inline/array-alloca.ll?rev=273952&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Inline/array-alloca.ll (added)
+++ llvm/trunk/test/Transforms/Inline/array-alloca.ll Mon Jun 27 17:31:53 2016
@@ -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
+}
+