0001-re-introduce-__builtin_add_overflow.patch

From 8ecef9e3ed8003a1cb6c1601cfa56d82f70e9900 Mon Sep 17 00:00:00 2001
From: "Urabe, Shyouhei" <[email protected]>
Date: Wed, 8 Mar 2017 13:14:04 +0900
Subject: [PATCH] re-introduce __builtin_add_overflow

r57789 (74cdd89) was gradually "improve"d by naruse through r57793 to
r57806, resulted in reverting the efect of r57789 while retaining its
complexity.  I think the current situation is slightly worse than
before (same output complicated source code).

Here I introduce __builtin_add_overflow again, which (I think) is what
naruse wanted to do in r57793.

Signed-off-by: Urabe, Shyouhei <[email protected]>
---
 include/ruby/ruby.h | 29 +++++++++++++----------------
 internal.h          |  7 +++----
 numeric.c           |  7 +++----
 3 files changed, 19 insertions(+), 24 deletions(-)

diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index 212ba82dd7..3cae4c0fd5 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -1505,15 +1505,14 @@ rb_integer_type_p(VALUE obj)
 #endif
 
 static inline int
-rb_long2fix_overflow(long l, VALUE *ptr)
+rb_long_is_fixable_p(long v)
 {
-    if (RB_FIXABLE(l)) {
-	*ptr = RB_LONG2FIX(l);
-	return 0;
-    }
-    else {
-	return 1;
-    }
+#ifdef HAVE_BUILTIN___BUILTIN_ADD_OVERFLOW
+    SIGNED_VALUE w;
+    return! __builtin_add_overflow(v, v, &w);
+#else
+    return RB_FIXABLE(v);
+#endif
 }
 
 #if SIZEOF_INT < SIZEOF_LONG
@@ -1523,11 +1522,10 @@ rb_long2fix_overflow(long l, VALUE *ptr)
 static inline VALUE
 rb_int2num_inline(int v)
 {
-    VALUE ret;
-    if (rb_long2fix_overflow(v, &ret))
-	return rb_int2big(v);
+    if (rb_long_is_fixable_p(v))
+        return RB_LONG2FIX(v);
     else
-	return ret;
+	return rb_int2big(v);
 }
 #define RB_INT2NUM(x) rb_int2num_inline(x)
 
@@ -1547,11 +1545,10 @@ rb_uint2num_inline(unsigned int v)
 static inline VALUE
 rb_long2num_inline(long v)
 {
-    VALUE ret;
-    if (rb_long2fix_overflow(v, &ret))
-	return rb_int2big(v);
+    if (rb_long_is_fixable_p(v))
+        return LONG2FIX(v);
     else
-	return ret;
+	return rb_int2big(v);
 }
 #define RB_LONG2NUM(x) rb_long2num_inline(x)
 
diff --git a/internal.h b/internal.h
index f2e726ce6e..9c8a2c00ae 100644
--- a/internal.h
+++ b/internal.h
@@ -1386,12 +1386,11 @@ rb_float_new_inline(double d)
 static inline VALUE
 rb_dbl2ival(double d)
 {
-    VALUE val;
-    if (rb_long2fix_overflow(d, &val)) {
-	return rb_dbl2big(d);
+    if (RB_FIXABLE(d)) {
+	return LONG2FIX((long)d);
     }
     else {
-	return val;
+	return rb_dbl2big(d);
     }
 }
 
diff --git a/numeric.c b/numeric.c
index 4f789e47a4..c728e309f4 100644
--- a/numeric.c
+++ b/numeric.c
@@ -3007,16 +3007,15 @@ VALUE
 rb_num2fix(VALUE val)
 {
     long v;
-    VALUE w;
 
     if (FIXNUM_P(val)) {
 	return val;
     }
-    else if (rb_long2fix_overflow((v = rb_num2long(val)), &w)) {
-	rb_raise(rb_eRangeError, "integer %ld out of range of fixnum", v);
+    else if (rb_long_is_fixable_p(v = rb_num2long(val))) {
+	return LONG2FIX(v);
     }
     else {
-	return w;
+	rb_raise(rb_eRangeError, "integer %ld out of range of fixnum", v);
     }
 }
 
-- 
2.12.0