[pure-lang-svn] SF.net SVN: pure-lang: [138] pure/trunk

[<ag...@us...>]

Revision: 138
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=138&view=rev
Author:   agraef
Date:     2008-05-26 21:28:33 -0700 (Mon, 26 May 2008)

Log Message:
-----------
Experimental support for tail-recursive short-circuit logical operators (&& and ||).

Modified Paths:
--------------
    pure/trunk/ChangeLog
    pure/trunk/interpreter.cc
    pure/trunk/interpreter.hh

Modified: pure/trunk/ChangeLog
===================================================================
--- pure/trunk/ChangeLog	2008-05-26 20:25:34 UTC (rev 137)
+++ pure/trunk/ChangeLog	2008-05-27 04:28:33 UTC (rev 138)
@@ -1,3 +1,11 @@
+2008-05-27  Albert Graef  <Dr....@t-...>
+
+	* interpreter.cc (toplevel_codegen): Experimental support for
+	tail-recursive short-circuit logical operators (&& and ||). Note
+	that this makes these operations behave slightly differently (more
+	like if-then-else) if they form the right-hand side of an
+	equation. But the advantages seem to outweigh the semantic quirks.
+
 2008-05-26  Albert Graef  <Dr....@t-...>
 
 	* interpreter.cc, runtime.cc: Overhaul of the shadow stack

Modified: pure/trunk/interpreter.cc
===================================================================
--- pure/trunk/interpreter.cc	2008-05-26 20:25:34 UTC (rev 137)
+++ pure/trunk/interpreter.cc	2008-05-27 04:28:33 UTC (rev 138)
@@ -3225,11 +3225,51 @@
 
 void interpreter::toplevel_codegen(expr x)
 {
+#if USE_FASTCC
   assert(!x.is_null());
-  if (x.tag() == EXPR::COND)
+  if (x.tag() == EXPR::COND) {
     toplevel_cond(x.xval1(), x.xval2(), x.xval3());
-  else
-    act_env().CreateRet(codegen(x));
+    return;
+  }
+  Env& e = act_env();
+#if TAILOPS
+  Builder& b = act_builder();
+  expr f; uint32_t n = count_args(x, f);
+  if (n == 2 && x.ttag() == EXPR::INT &&
+      x.xval1().xval2().ttag() != EXPR::DBL &&
+      x.xval2().ttag() != EXPR::DBL) {
+    if (f.ftag() == symtab.or_sym().f) {
+      Value *u = get_int(x.xval1().xval2());
+      Value *condv = b.CreateICmpNE(u, Zero, "cond");
+      BasicBlock *iftruebb = new BasicBlock("iftrue");
+      BasicBlock *iffalsebb = new BasicBlock("iffalse");
+      b.CreateCondBr(condv, iftruebb, iffalsebb);
+      e.f->getBasicBlockList().push_back(iftruebb);
+      b.SetInsertPoint(iftruebb);
+      e.CreateRet(ibox(One));
+      e.f->getBasicBlockList().push_back(iffalsebb);
+      b.SetInsertPoint(iffalsebb);
+      toplevel_codegen(x.xval2());
+    } else if (f.ftag() == symtab.and_sym().f) {
+      Value *u = get_int(x.xval1().xval2());
+      Value *condv = b.CreateICmpNE(u, Zero, "cond");
+      BasicBlock *iftruebb = new BasicBlock("iftrue");
+      BasicBlock *iffalsebb = new BasicBlock("iffalse");
+      b.CreateCondBr(condv, iftruebb, iffalsebb);
+      e.f->getBasicBlockList().push_back(iffalsebb);
+      b.SetInsertPoint(iffalsebb);
+      e.CreateRet(ibox(Zero));
+      e.f->getBasicBlockList().push_back(iftruebb);
+      b.SetInsertPoint(iftruebb);
+      toplevel_codegen(x.xval2());
+    } else
+      e.CreateRet(codegen(x));
+  } else
+#endif
+    e.CreateRet(codegen(x));
+#else
+  act_env().CreateRet(codegen(x));
+#endif
 }
 
 Value *interpreter::codegen(expr x)

Modified: pure/trunk/interpreter.hh
===================================================================
--- pure/trunk/interpreter.hh	2008-05-26 20:25:34 UTC (rev 137)
+++ pure/trunk/interpreter.hh	2008-05-27 04:28:33 UTC (rev 138)
@@ -28,6 +28,11 @@
 /* Experimental support for the "fast" calling convention which is needed to
    get tail call elimination. */
 #define USE_FASTCC 1
+/* Experimental support for tail-recursive short-circuit logical operators (&&
+   and ||). This will only have an effect if USE_FASTCC is enabled. Note that
+   if you disable this option, && and || will still be short-curcuit, they
+   just won't be tail-recursive in their second operand any more. */
+#define TAILOPS 1
 
 using namespace std;
 


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