From 0164b8ff70e814cd60621b0fcfbc5b86637efbb3 Mon Sep 17 00:00:00 2001
From: Tobias Grosser <tobias@grosser.es>
Date: Thu, 13 Aug 2015 08:07:39 +0000
Subject: [PATCH] Enable code generation of scalar dependences from function
 arguments

This change extends the BlockGenerator to not only allow Instructions as
base elements of scalar dependences, but any llvm::Value. This allows
us to code-generate scalar dependences which reference function arguments, as
they arise when moddeling read-only scalar dependences.

llvm-svn: 244874
---
 polly/include/polly/CodeGen/BlockGenerators.h |  8 +++----
 polly/lib/CodeGen/BlockGenerators.cpp         |  4 ++--
 polly/test/Isl/CodeGen/read-only-scalars.ll   | 33 +++++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 6 deletions(-)
 create mode 100644 polly/test/Isl/CodeGen/read-only-scalars.ll

diff --git a/polly/include/polly/CodeGen/BlockGenerators.h b/polly/include/polly/CodeGen/BlockGenerators.h
index 8c18f0c..b787234 100644
--- a/polly/include/polly/CodeGen/BlockGenerators.h
+++ b/polly/include/polly/CodeGen/BlockGenerators.h
@@ -67,7 +67,7 @@ public:
   ///@{
 
   /// @see The ScalarMap and PHIOpMap member.
-  using ScalarAllocaMapTy = DenseMap<Instruction *, AllocaInst *>;
+  using ScalarAllocaMapTy = DenseMap<Value *, AllocaInst *>;
 
   /// @brief Simple vector of instructions to store escape users.
   using EscapeUserVectorTy = SmallVector<Instruction *, 4>;
@@ -302,13 +302,13 @@ protected:
   /// If no alloca was mapped to @p ScalarBase in @p Map a new one is created
   /// and named after @p ScalarBase with the suffix @p NameExt.
   ///
-  /// @param ScalarBase The demoted scalar instruction.
-  /// @param Map        The map we should look for a mapped alloca instruction.
+  /// @param ScalarBase The demoted scalar value.
+  /// @param Map        The map we should look for a mapped alloca value.
   /// @param NameExt    The suffix we add to the name of a new created alloca.
   /// @param IsNew      If set it will hold true iff the alloca was created.
   ///
   /// @returns The alloca for @p ScalarBase in @p Map.
-  AllocaInst *getOrCreateAlloca(Instruction *ScalarBase, ScalarAllocaMapTy &Map,
+  AllocaInst *getOrCreateAlloca(Value *ScalarBase, ScalarAllocaMapTy &Map,
                                 const char *NameExt = ".s2a",
                                 bool *IsNew = nullptr);
 
diff --git a/polly/lib/CodeGen/BlockGenerators.cpp b/polly/lib/CodeGen/BlockGenerators.cpp
index 8e8e40c..fb46b09 100644
--- a/polly/lib/CodeGen/BlockGenerators.cpp
+++ b/polly/lib/CodeGen/BlockGenerators.cpp
@@ -352,7 +352,7 @@ void BlockGenerator::copyBB(ScopStmt &Stmt, BasicBlock *BB, BasicBlock *CopyBB,
     handleOutsideUsers(R, &Inst, BBMap[&Inst]);
 }
 
-AllocaInst *BlockGenerator::getOrCreateAlloca(Instruction *ScalarBase,
+AllocaInst *BlockGenerator::getOrCreateAlloca(Value *ScalarBase,
                                               ScalarAllocaMapTy &Map,
                                               const char *NameExt,
                                               bool *IsNew) {
@@ -433,7 +433,7 @@ void BlockGenerator::generateScalarLoads(ScopStmt &Stmt,
     if (!MA.isScalar() || !MA.isRead())
       continue;
 
-    auto Base = cast<Instruction>(MA.getBaseAddr());
+    auto Base = MA.getBaseAddr();
 
     if (MA.getScopArrayInfo()->isPHI())
       Address = getOrCreateAlloca(Base, PHIOpMap, ".phiops");
diff --git a/polly/test/Isl/CodeGen/read-only-scalars.ll b/polly/test/Isl/CodeGen/read-only-scalars.ll
new file mode 100644
index 0000000..f42d07e
--- /dev/null
+++ b/polly/test/Isl/CodeGen/read-only-scalars.ll
@@ -0,0 +1,33 @@
+; RUN: opt %loadPolly -polly-analyze-read-only-scalars=false -polly-codegen -polly-no-early-exit -S < %s | FileCheck %s
+; RUN: opt %loadPolly -polly-analyze-read-only-scalars=true -polly-codegen -polly-no-early-exit -S < %s | FileCheck %s -check-prefix=SCALAR
+
+; CHECK-NOT: alloca
+
+; SCALAR-LABEL: entry:
+; SCALAR-NEXT: %scalar.s2a = alloca float
+
+; SCALAR:  %scalar.s2a.reload = load float, float* %scalar.s2a
+; SCALAR-NEXT:  %p_sum = fadd float %val_p_scalar_, %scalar.s2a.reload
+
+define void @foo(float* noalias %A, float %scalar) {
+entry:
+  br label %loop
+
+loop:
+  %indvar = phi i64 [0, %entry], [%indvar.next, %loop.backedge]
+  br label %stmt1
+
+stmt1:
+  %val = load float, float* %A
+  %sum = fadd float %val, %scalar
+  store float %sum, float* %A
+  br label %loop.backedge
+
+loop.backedge:
+  %indvar.next = add i64 %indvar, 1
+  %cond = icmp sle i64 %indvar, 100
+  br i1 %cond, label %loop, label %exit
+
+exit:
+  ret void
+}
-- 
2.7.4