Memaccess: Codegeneration for a simple access function change

Code is generated for a simple access function change imported
from JSCOP file. An access of A[i] is changed to A[0]. The code
for A[0] is generated directly without refering to isl function calls.

llvm-svn: 136789

polly/include/polly/ScopInfo.h

@@ -130,6 +130,11 @@ public:
     return BaseName;
   }
 
+  /// @brief Get the new access function imported from JSCOP file
+  isl_map *getNewAccessFunction() {
+    return newAccessRelation;
+  }
+
   /// @brief Get the stride of this memory access in the specified domain
   ///        subset.
   isl_set *getStride(const isl_set *domainSubset) const;

polly/lib/CodeGeneration.cpp

@@ -314,9 +314,36 @@ public:
     return vector;
   }
 
+  /// @brief Get the new operand address according to the changed access in
+  ///        JSCOP file.
+  Value *getNewAccessOperand(isl_map *newAccessRelation, Value *baseAddr,
+                             const Value *OldOperand, ValueMapT &BBMap) {
+    unsigned accessIdx = 0;
+    Value *newOperand = Builder.CreateStructGEP(baseAddr,
+                                                accessIdx, "p_newarrayidx_");
+    return newOperand;
+  }
+
+  /// @brief Generate the operand address
+  Value *generateLocationAccessed(const Instruction *Inst,
+                                  const Value *pointer, ValueMapT &BBMap ) {
+    MemoryAccess &Access = statement.getAccessFor(Inst);
+    isl_map *newAccessRelation = Access.getNewAccessFunction();
+    if (!newAccessRelation) {
+      Value *newPointer = getOperand(pointer, BBMap);
+      return newPointer;
+    }
+    
+    Value *baseAddr = const_cast<Value*>(Access.getBaseAddr());
+    Value *newPointer = getNewAccessOperand(newAccessRelation, baseAddr,
+                                            pointer, BBMap);
+    return newPointer;
+  }
+
   Value *generateScalarLoad(const LoadInst *load, ValueMapT &BBMap) {
     const Value *pointer = load->getPointerOperand();
-    Value *newPointer = getOperand(pointer, BBMap);
+    const Instruction *Inst = dyn_cast<Instruction>(load);
+    Value *newPointer = generateLocationAccessed(Inst, pointer, BBMap);
     Value *scalarLoad = Builder.CreateLoad(newPointer,
                                            load->getNameStr() + "_p_scalar_");
     return scalarLoad;

polly/test/CodeGen/MemAccess/memaccess_codegen_simple.c

@@ -0,0 +1,8 @@
+int A[100];
+
+int memaccess_codegen_simple () {
+  for (int i = 0; i < 12; i++)
+    A[13] = A[i] + A[i-1];
+
+  return 0;
+}

polly/test/CodeGen/MemAccess/memaccess_codegen_simple.ll

@@ -0,0 +1,34 @@
+;RUN: opt %loadPolly -polly-import-jscop -polly-import-jscop-dir=`dirname %s` -polly-import-jscop-postfix=transformed -polly-codegen -instnamer %s -S | FileCheck %s
+; ModuleID = 'memaccess_codegen_simple.ll'
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
+target triple = "i386-pc-linux-gnu"
+
+@A = common global [100 x i32] zeroinitializer, align 4
+
+define i32 @memaccess_codegen_simple() nounwind {
+entry:
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %tmp1 = phi i32 [ 0, %entry ], [ %inc, %for.inc ]
+  %tmp = add i32 %tmp1, -1
+  %arrayidx4 = getelementptr [100 x i32]* @A, i32 0, i32 %tmp
+  %arrayidx = getelementptr [100 x i32]* @A, i32 0, i32 %tmp1
+  %exitcond = icmp ne i32 %tmp1, 12
+  br i1 %exitcond, label %for.body, label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %tmp2 = load i32* %arrayidx, align 4
+  %tmp5 = load i32* %arrayidx4, align 4
+  %add = add nsw i32 %tmp2, %tmp5
+  store i32 %add, i32* getelementptr inbounds ([100 x i32]* @A, i32 0, i32 13), align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %inc = add nsw i32 %tmp1, 1
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond
+  ret i32 0
+}
+; CHECK: load i32* getelementptr inbounds ([100 x i32]* @A, i32 0, i32 0)

polly/test/CodeGen/MemAccess/memaccess_codegen_simple___%for.cond---%for.end.jscop

@@ -0,0 +1,25 @@
+{
+   "context" : "{ [] }",
+   "name" : "for.cond => for.end",
+   "statements" : [
+      {
+         "accesses" : [
+            {
+               "kind" : "read",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[i0] }"
+            },
+            {
+               "kind" : "read",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[-1 + i0] }"
+            },
+            {
+               "kind" : "write",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[13] }"
+            }
+         ],
+         "domain" : "{ Stmt_for_body[i0] : i0 >= 0 and i0 <= 11 }",
+         "name" : "Stmt_for_body",
+         "schedule" : "{ Stmt_for_body[i0] -> scattering[0, i0, 0] }"
+      }
+   ]
+}

polly/test/CodeGen/MemAccess/memaccess_codegen_simple___%for.cond---%for.end.jscop.transformed

@@ -0,0 +1,25 @@
+{
+   "context" : "{ [] }",
+   "name" : "for.cond => for.end",
+   "statements" : [
+      {
+         "accesses" : [
+            {
+               "kind" : "read",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[0] }"
+            },
+            {
+               "kind" : "read",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[-1 + i0] }"
+            },
+            {
+               "kind" : "write",
+               "relation" : "{ Stmt_for_body[i0] -> MemRef_A[13] }"
+            }
+         ],
+         "domain" : "{ Stmt_for_body[i0] : i0 >= 0 and i0 <= 11 }",
+         "name" : "Stmt_for_body",
+         "schedule" : "{ Stmt_for_body[i0] -> scattering[0, i0, 0] }"
+      }
+   ]
+}