APInt-ify the gep scaling code, so that it correctly handles the case where

the scale overflows pointer-sized arithmetic. This fixes PR5281.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84954 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
index adcc532..d862e40 100644 (file)
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuild.cpp
@@ -2666,7 +2666,8 @@ void SelectionDAGLowering::visitGetElementPtr(User &I) {
       }
 
       // N = N + Idx * ElementSize;
-      uint64_t ElementSize = TD->getTypeAllocSize(Ty);
+      APInt ElementSize = APInt(TLI.getPointerTy().getSizeInBits(),
+                                TD->getTypeAllocSize(Ty));
       SDValue IdxN = getValue(Idx);
 
       // If the index is smaller or larger than intptr_t, truncate or extend
@@ -2676,13 +2677,13 @@ void SelectionDAGLowering::visitGetElementPtr(User &I) {
       // If this is a multiply by a power of two, turn it into a shl
       // immediately.  This is a very common case.
       if (ElementSize != 1) {
-        if (isPowerOf2_64(ElementSize)) {
-          unsigned Amt = Log2_64(ElementSize);
+        if (ElementSize.isPowerOf2()) {
+          unsigned Amt = ElementSize.logBase2();
           IdxN = DAG.getNode(ISD::SHL, getCurDebugLoc(),
                              N.getValueType(), IdxN,
                              DAG.getConstant(Amt, TLI.getPointerTy()));
         } else {
-          SDValue Scale = DAG.getIntPtrConstant(ElementSize);
+          SDValue Scale = DAG.getConstant(ElementSize, TLI.getPointerTy());
           IdxN = DAG.getNode(ISD::MUL, getCurDebugLoc(),
                              N.getValueType(), IdxN, Scale);
         }

diff --git a/test/CodeGen/X86/large-gep-scale.ll b/test/CodeGen/X86/large-gep-scale.ll
new file mode 100644 (file)
index 0000000..143294e
--- /dev/null
+++ b/test/CodeGen/X86/large-gep-scale.ll
@@ -0,0 +1,12 @@
+; RUN: llc < %s -march=x86 | FileCheck %s
+; PR5281
+
+; After scaling, this type doesn't fit in memory. Codegen should generate
+; correct addressing still.
+
+; CHECK: shll $2, %edx
+
+define fastcc i32* @_ada_smkr([2147483647 x i32]* %u, i32 %t) nounwind {
+  %x = getelementptr [2147483647 x i32]* %u, i32 %t, i32 0
+  ret i32* %x
+}