Files
ispc/builtins/dispatch.ll
Matt Pharr 1d9201fe3d Add "generic" 4, 8, and 16-wide targets.
When used, these targets end up with calls to undefined functions for all
of the various special vector stuff ispc needs to compile ispc programs
(masked store, gather, min/max, sqrt, etc.).

These targets are not yet useful for anything, but are a step toward
having an option to C++ code with calls out to intrinsics.

Reorganized the directory structure a bit and put the LLVM bitcode used
to define target-specific stuff (as well as some generic built-ins stuff)
into a builtins/ directory.

Note that for building on Windows, it's now necessary to set a LLVM_VERSION
environment variable (with values like LLVM_2_9, LLVM_3_0, LLVM_3_1svn, etc.)
2011-12-19 13:46:50 -08:00

124 lines
4.5 KiB
LLVM

;; Copyright (c) 2011, Intel Corporation
;; All rights reserved.
;;
;; Redistribution and use in source and binary forms, with or without
;; modification, are permitted provided that the following conditions are
;; met:
;;
;; * Redistributions of source code must retain the above copyright
;; notice, this list of conditions and the following disclaimer.
;;
;; * Redistributions in binary form must reproduce the above copyright
;; notice, this list of conditions and the following disclaimer in the
;; documentation and/or other materials provided with the distribution.
;;
;; * Neither the name of Intel Corporation nor the names of its
;; contributors may be used to endorse or promote products derived from
;; this software without specific prior written permission.
;;
;;
;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
;; IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
;; TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
;; PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
;; OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
;; EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
;; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;; PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;; This file defines various functions that are used when generating the
;; the "dispatch" object/assembly file that has entrypoints for each
;; exported function in a module that dispatch to the best available
;; variant of that function that will run on the system's CPU.
;; Stores the best target ISA that the system on which we're actually
;; running supports. -1 represents "uninitialized", otherwise this value
;; should correspond to one of the enumerant values of Target::ISA from
;; ispc.h.
@__system_best_isa = internal global i32 -1
declare void @abort() noreturn
;; The below is the result of running "clang -O2 -emit-llvm -c -o -" on the
;; following code... Specifically, __get_system_isa should return a value
;; corresponding to one of the Target::ISA enumerant values that gives the
;; most capable ISA that the curremt system can run.
;;
;; #ifdef _MSC_VER
;; extern void __stdcall __cpuid(int info[4], int infoType);
;; #else
;; static void __cpuid(int info[4], int infoType) {
;; __asm__ __volatile__ ("cpuid"
;; : "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
;; : "0" (infoType));
;; }
;; #endif
;;
;; int32_t __get_system_isa() {
;; int info[4];
;; __cpuid(info, 1);
;; /* NOTE: the values returned below must be the same as the
;; corresponding enumerant values in Target::ISA. */
;; if ((info[2] & (1 << 28)) != 0)
;; return 2; // AVX
;; else if ((info[2] & (1 << 19)) != 0)
;; return 1; // SSE4
;; else if ((info[3] & (1 << 26)) != 0)
;; return 0; // SSE2
;; else
;; abort();
;; }
%0 = type { i32, i32, i32, i32 }
define i32 @__get_system_isa() nounwind ssp {
%1 = tail call %0 asm sideeffect "cpuid", "={ax},={bx},={cx},={dx},0,~{dirflag},~{fpsr},~{flags}"(i32 1) nounwind
%2 = extractvalue %0 %1, 2
%3 = extractvalue %0 %1, 3
%4 = and i32 %2, 268435456
%5 = icmp eq i32 %4, 0
br i1 %5, label %6, label %13
; <label>:6 ; preds = %0
%7 = and i32 %2, 524288
%8 = icmp eq i32 %7, 0
br i1 %8, label %9, label %13
; <label>:9 ; preds = %6
%10 = and i32 %3, 67108864
%11 = icmp eq i32 %10, 0
br i1 %11, label %12, label %13
; <label>:12 ; preds = %9
tail call void @abort() noreturn nounwind
unreachable
; <label>:13 ; preds = %9, %6, %0
%.0 = phi i32 [ 2, %0 ], [ 1, %6 ], [ 0, %9 ]
ret i32 %.0
}
;; This function is called by each of the dispatch functions we generate;
;; it sets @__system_best_isa if it is unset.
define void @__set_system_isa() {
entry:
%bi = load i32* @__system_best_isa
%unset = icmp eq i32 %bi, -1
br i1 %unset, label %set_system_isa, label %done
set_system_isa:
%bival = call i32 @__get_system_isa()
store i32 %bival, i32* @__system_best_isa
ret void
done:
ret void
}