Eli Friedman 0d586d06a7 [compiler-rt] Add back ARM EABI aliases where legal.
r303188 removed all the uses of aliases for EABI functions from
compiler-rt, because some of them had mismatched calling conventions.
Obviously, we can't use aliases for functions which don't have the same
calling convention, but that's only an issue for floating-point
functions with the hardfloat ABI.  In other cases, the stubs increase
size and reduce performance for no benefit.

This patch adds back the aliases, with appropriate checks to make sure
they're only used in cases where the calling convention matches.

llvm-svn: 314851
2017-10-03 21:25:07 +00:00

68 lines
2.0 KiB
C

//===-- lib/floatsisf.c - integer -> single-precision 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 integer to single-precision conversion for the
// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
// mode.
//
//===----------------------------------------------------------------------===//
#define SINGLE_PRECISION
#include "fp_lib.h"
#include "int_lib.h"
COMPILER_RT_ABI fp_t
__floatsisf(int a) {
const int aWidth = sizeof a * CHAR_BIT;
// Handle zero as a special case to protect clz
if (a == 0)
return fromRep(0);
// All other cases begin by extracting the sign and absolute value of a
rep_t sign = 0;
if (a < 0) {
sign = signBit;
a = -a;
}
// Exponent of (fp_t)a is the width of abs(a).
const int exponent = (aWidth - 1) - __builtin_clz(a);
rep_t result;
// Shift a into the significand field, rounding if it is a right-shift
if (exponent <= significandBits) {
const int shift = significandBits - exponent;
result = (rep_t)a << shift ^ implicitBit;
} else {
const int shift = exponent - significandBits;
result = (rep_t)a >> shift ^ implicitBit;
rep_t round = (rep_t)a << (typeWidth - shift);
if (round > signBit) result++;
if (round == signBit) result += result & 1;
}
// Insert the exponent
result += (rep_t)(exponent + exponentBias) << significandBits;
// Insert the sign bit and return
return fromRep(result | sign);
}
#if defined(__ARM_EABI__)
#if defined(COMPILER_RT_ARMHF_TARGET)
AEABI_RTABI fp_t __aeabi_i2f(int a) {
return __floatsisf(a);
}
#else
AEABI_RTABI fp_t __aeabi_i2f(int a) COMPILER_RT_ALIAS(__floatsisf);
#endif
#endif