Refactor float to integer conversion to share the same code.

80bit Intel/PPC long double is excluded due to lacking support
for the abstraction. Consistently provide saturation logic.
Extend to long double on 128bit IEEE extended platforms.

Initial patch with test cases from GuanHong Liu.
Reviewed by Steve Canon.

Differential Revision: http://reviews.llvm.org/D2804


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@231965 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 42 deletions

diff --git a/lib/builtins/fixdfsi.c b/lib/builtins/fixdfsi.c
index 88b2ff5e7..704e65bc4 100644
--- a/lib/builtins/fixdfsi.c
+++ b/lib/builtins/fixdfsi.c
@@ -1,50 +1,22 @@
-//===-- lib/fixdfsi.c - Double-precision -> integer conversion ----*- C -*-===//
-//
-//                     The LLVM Compiler Infrastructure
-//
-// This file is dual licensed under the MIT and the University of Illinois Open
-// Source Licenses. See LICENSE.TXT for details.
-//
-//===----------------------------------------------------------------------===//
-//
-// This file implements double-precision to integer conversion for the
-// compiler-rt library.  No range checking is performed; the behavior of this
-// conversion is undefined for out of range values in the C standard.
-//
-//===----------------------------------------------------------------------===//
+/* ===-- fixdfsi.c - Implement __fixdfsi -----------------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ */
 
 #define DOUBLE_PRECISION
 #include "fp_lib.h"
-
-#include "int_lib.h"
+typedef si_int fixint_t;
+typedef su_int fixuint_t;
+#include "fp_fixint_impl.inc"
 
 ARM_EABI_FNALIAS(d2iz, fixdfsi)
 
-COMPILER_RT_ABI int
+COMPILER_RT_ABI si_int
 __fixdfsi(fp_t a) {
-    
-    // Break a into sign, exponent, significand
-    const rep_t aRep = toRep(a);
-    const rep_t aAbs = aRep & absMask;
-    const int sign = aRep & signBit ? -1 : 1;
-    const int exponent = (aAbs >> significandBits) - exponentBias;
-    const rep_t significand = (aAbs & significandMask) | implicitBit;
-    
-    // If 0 < exponent < significandBits, right shift to get the result.
-    if ((unsigned int)exponent < significandBits) {
-        return sign * (significand >> (significandBits - exponent));
-    }
-    
-    // If exponent is negative, the result is zero.
-    else if (exponent < 0) {
-        return 0;
-    }
-    
-    // If significandBits < exponent, left shift to get the result.  This shift
-    // may end up being larger than the type width, which incurs undefined
-    // behavior, but the conversion itself is undefined in that case, so
-    // whatever the compiler decides to do is fine.
-    else {
-        return sign * (significand << (exponent - significandBits));
-    }
+    return __fixint(a);
 }