[Beignet] [PATCH 2/2] GBE: optimize GEP constant offset calculation.

[Zhigang Gong]

If the type is array or vector, we do not need to iterate each element.
We can compute it directly.

Signed-off-by: Zhigang Gong <zhigang.gong at intel.com>
---
 backend/src/llvm/llvm_passes.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/backend/src/llvm/llvm_passes.cpp b/backend/src/llvm/llvm_passes.cpp
index 24ad9d0..8708ea9 100644
--- a/backend/src/llvm/llvm_passes.cpp
+++ b/backend/src/llvm/llvm_passes.cpp
@@ -275,7 +275,7 @@ namespace gbe
     Value* currentAddrInst = 
       new PtrToIntInst(parentPointer, IntegerType::get(GEPInst->getContext(), ptrSize), "", GEPInst);
 
-    uint32_t constantOffset = 0;
+    int32_t constantOffset = 0;
 
     for(uint32_t op=1; op<GEPInst->getNumOperands(); ++op)
     {
@@ -286,9 +286,10 @@ namespace gbe
         int32_t offset = 0;
         TypeIndex = ConstOP->getZExtValue();
         int32_t step = TypeIndex > 0 ? 1 : -1;
-        if (op == 1) {
+        if (op == 1 || CompTy->isVectorTy() || CompTy->isArrayTy()) {
           if (TypeIndex != 0) {
-            Type *elementType = (cast<PointerType>(parentPointer->getType()))->getElementType();
+            Type *elementType = (op == 1) ? (cast<PointerType>(parentPointer->getType()))->getElementType()
+                                          : CompTy->getTypeAtIndex((uint32_t)0);
             uint32_t elementSize = getTypeByteSize(unit, elementType);
             uint32_t align = getAlignmentByte(unit, elementType);
             elementSize += getPadding(elementSize, align);
-- 
1.8.3.2