MIR Optimise - Fixed replacement of unified temporaries

4 files changed, 21 insertions, 12 deletions

diff --git a/src/mir/helpers.cpp b/src/mir/helpers.cpp
index e731fae7..9750b978 100644
--- a/src/mir/helpers.cpp
+++ b/src/mir/helpers.cpp
@@ -11,10 +11,9 @@
 #include <hir/type.hpp>
 #include <mir/mir.hpp>
 
-void ::MIR::TypeResolve::print_msg(const char* tag, ::std::function<void(::std::ostream& os)> cb) const
+void ::MIR::TypeResolve::fmt_pos(::std::ostream& os) const
 {
-    auto& os = ::std::cerr;
-    os << "MIR " << tag << ": " << this->m_path << " BB" << this->bb_idx << "/";
+    os << this->m_path << " BB" << this->bb_idx << "/";
     if( this->stmt_idx == STMT_TERM ) {
         os << "TERM";
     }
@@ -22,6 +21,12 @@ void ::MIR::TypeResolve::print_msg(const char* tag, ::std::function<void(::std::
         os << this->stmt_idx;
     }
     os << ": ";
+}
+void ::MIR::TypeResolve::print_msg(const char* tag, ::std::function<void(::std::ostream& os)> cb) const
+{
+    auto& os = ::std::cerr;
+    os << "MIR " << tag << ": ";
+    fmt_pos(os);
     cb(os);
     os << ::std::endl;
     abort();
diff --git a/src/mir/helpers.hpp b/src/mir/helpers.hpp
index 40dbd4a3..cc0766ec 100644
--- a/src/mir/helpers.hpp
+++ b/src/mir/helpers.hpp
@@ -33,6 +33,7 @@ struct CheckFailure:
 #define MIR_BUG(state, ...) do { (state).print_bug( [&](auto& _os){_os << __VA_ARGS__; } ); throw ""; } while(0)
 #define MIR_ASSERT(state, cnd, ...) do { if( !(cnd) ) (state).print_bug( [&](auto& _os){_os << "ASSERT " #cnd " failed - " << __VA_ARGS__; } ); } while(0)
 #define MIR_TODO(state, ...) do { (state).print_todo( [&](auto& _os){_os << __VA_ARGS__; } ); throw ""; } while(0)
+#define MIR_DEBUG(state, ...) do { DEBUG(FMT_CB(_ss, (state).fmt_pos(_ss);) << __VA_ARGS__); } while(0)
 
 class TypeResolve
 {
@@ -79,6 +80,7 @@ public:
         this->stmt_idx = STMT_TERM;
     }
 
+    void fmt_pos(::std::ostream& os) const;
     void print_bug(::std::function<void(::std::ostream& os)> cb) const {
         print_msg("ERROR", cb);
     }
@@ -95,5 +97,4 @@ public:
     const ::HIR::TypeRef* is_type_owned_box(const ::HIR::TypeRef& ty) const;
 };
 
-
 }   // namespace MIR
diff --git a/src/mir/mir.cpp b/src/mir/mir.cpp
index 8daeef39..157071c7 100644
--- a/src/mir/mir.cpp
+++ b/src/mir/mir.cpp
@@ -108,7 +108,7 @@ namespace MIR {
             os << "Deref(" << *e.val << ")";
             ),
         (Index,
-            os << "Deref(" << *e.val << ", " << *e.idx << ")";
+            os << "Index(" << *e.val << ", " << *e.idx << ")";
             ),
         (Downcast,
             os << "Downcast(" << e.variant_index << ", " << *e.val << ")";
diff --git a/src/mir/optimise.cpp b/src/mir/optimise.cpp
index 7e5243fb..a0b42e0d 100644
--- a/src/mir/optimise.cpp
+++ b/src/mir/optimise.cpp
@@ -60,9 +60,10 @@ namespace {
             return visit_mir_lvalue_mut(*e.val, is_write, cb);
             ),
         (Index,
-            if( visit_mir_lvalue_mut(*e.val, is_write, cb) )
-                return true;
-            return visit_mir_lvalue_mut(*e.idx, false, cb);
+            bool rv = false;
+            rv |= visit_mir_lvalue_mut(*e.val, is_write, cb);
+            rv |= visit_mir_lvalue_mut(*e.idx, false, cb);
+            return rv;
             ),
         (Downcast,
             return visit_mir_lvalue_mut(*e.val, is_write, cb);
@@ -196,13 +197,13 @@ namespace {
         for(unsigned int block_idx = 0; block_idx < fcn.blocks.size(); block_idx ++)
         {
             auto& block = fcn.blocks[block_idx];
-            if( block.terminator.tag() == ::MIR::Terminator::TAGDEAD )
-                continue ;
             for(auto& stmt : block.statements)
             {
                 state.set_cur_stmt(block_idx, (&stmt - &block.statements.front()));
                 visit_mir_lvalues_mut(stmt, cb);
             }
+            if( block.terminator.tag() == ::MIR::Terminator::TAGDEAD )
+                continue ;
             state.set_cur_stmt_term(block_idx);
             visit_mir_lvalues_mut(block.terminator, cb);
         }
@@ -606,7 +607,7 @@ bool MIR_Optimise_UnifyTemporaries(::MIR::TypeResolve& state, ::MIR::Function& f
             // Variables are of the same type, check if they overlap
             if( tmp_lifetimes[tmpidx].overlaps( tmp_lifetimes[i] ) )
                 continue ;
-            // They overlap, unify 
+            // They overlap, unify
             tmp_lifetimes[tmpidx].unify( tmp_lifetimes[i] );
             replacements[i] = tmpidx;
             replacement_needed = true;
@@ -622,9 +623,10 @@ bool MIR_Optimise_UnifyTemporaries(::MIR::TypeResolve& state, ::MIR::Function& f
                 auto it = replacements.find(ve->idx);
                 if( it != replacements.end() )
                 {
+                    MIR_DEBUG(state, lv << " => Temporary(" << it->second << ")");
                     ve->idx = it->second;
+                    return true;
                 }
-                return true;
             }
             return false;
             });
@@ -1342,6 +1344,7 @@ bool MIR_Optimise_GarbageCollect(::MIR::TypeResolve& state, ::MIR::Function& fcn
                 if( lv.is_Temporary() ) {
                     auto& e = lv.as_Temporary();
                     MIR_ASSERT(state, e.idx < temp_rewrite_table.size(), "Temporary out of range - " << lv);
+                    // If the table entry for this temporary is !0, it wasn't marked as used
                     MIR_ASSERT(state, temp_rewrite_table.at(e.idx) != ~0u, "LValue " << lv << " incorrectly marked as unused");
                     e.idx = temp_rewrite_table.at(e.idx);
                 }