From ca7cc4744eaa14c6221bc57f5548c59616343788 Mon Sep 17 00:00:00 2001
From: Matt Pharr <matt.pharr@intel.com>
Date: Thu, 12 Apr 2012 06:08:19 -0700
Subject: [PATCH] Fix bug with taking references of temporaries.

Previously, the compiler would crash if e.g. the program passed a
temporary value to a function taking a const reference.  This change
fixes ReferenceExpr::GetValue() to handle this case and allocate
temporary storage for the temporary so that the pointer to that
storage can be used for the reference value.
---
 expr.cpp                    | 29 ++++++++++++++++++++++++++++-
 tests/ref-as-temporary.ispc | 14 ++++++++++++++
 2 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 tests/ref-as-temporary.ispc

diff --git a/expr.cpp b/expr.cpp
index dab2b416..cbef1622 100644
--- a/expr.cpp
+++ b/expr.cpp
@@ -6861,7 +6861,34 @@ ReferenceExpr::ReferenceExpr(Expr *e, SourcePos p)
 llvm::Value *
 ReferenceExpr::GetValue(FunctionEmitContext *ctx) const {
     ctx->SetDebugPos(pos);
-    return expr ? expr->GetLValue(ctx) : NULL;
+    if (expr == NULL) {
+        Assert(m->errorCount > 0);
+        return NULL;
+    }
+    
+    llvm::Value *value = expr->GetLValue(ctx);
+    if (value != NULL)
+        return value;
+
+    // value is NULL if the expression is a temporary; in this case, we'll
+    // allocate storage for it so that we can return the pointer to that...
+    const Type *type;
+    LLVM_TYPE_CONST llvm::Type *llvmType;
+    if ((type = expr->GetType()) == NULL ||
+        (llvmType = type->LLVMType(g->ctx)) == NULL) {
+        Assert(m->errorCount > 0);
+        return NULL;
+    }
+
+    value = expr->GetValue(ctx);
+    if (value == NULL) {
+        Assert(m->errorCount > 0);
+        return NULL;
+    }
+
+    llvm::Value *ptr = ctx->AllocaInst(llvmType);
+    ctx->StoreInst(value, ptr);
+    return ptr;
 }
 
 
diff --git a/tests/ref-as-temporary.ispc b/tests/ref-as-temporary.ispc
new file mode 100644
index 00000000..1b167da6
--- /dev/null
+++ b/tests/ref-as-temporary.ispc
@@ -0,0 +1,14 @@
+
+export uniform int width() { return programCount; }
+
+
+int func(const int &a) { return a+1; }
+int bar() { return 0; }
+
+export void f_f(uniform float RET[], uniform float aFOO[]) {
+    RET[programIndex] = func(bar());
+}
+
+export void result(uniform float RET[]) {
+    RET[programIndex] = 1;
+}