This is part of an ongoing attempt at making 512 bit vectors illegal in the X86 backend type legalizer due to CPU frequency penalties associated with wide vectors on Skylake Server CPUs. We want the loop vectorizer to be able to emit IR containing wide vectors as intermediate operations in vectorized code and allow these wide vectors to be legalized to 256 bits by the X86 backend even though we are targetting a CPU that supports 512 bit vectors. This is similar to what happens with an AVX2 CPU, the vectorizer can emit wide vectors and the backend will split them. We want this splitting behavior, but still be able to use new Skylake instructions that work on 256-bit vectors and support things like masking and gather/scatter.
Of course if the user uses explicit vector code in their source code we need to not split those operations. Especially if they have used any of the 512-bit vector intrinsics from immintrin.h. And we need to make it so that merely using the intrinsics produces the expected code in order to be backwards compatible.
To support this goal, this patch adds a new IR function attribute "min-legal-vector-width" that can indicate the need for a minimum vector width to be legal in the backend. We need to ensure this attribute is set to the largest vector width needed by any intrinsics from immintrin.h that the function uses. The inliner will be reponsible for merging this attribute when a function is inlined. We may also need a way to limit inlining in the future as well, but we can discuss that in the future.
To make things more complicated, there are two different ways intrinsics are implemented in immintrin.h. Either as an always_inline function containing calls to builtins(can be target specific or target independent) or vector extension code. Or as a macro wrapper around a taget specific builtin. I believe I've removed all cases where the macro was around a target independent builtin.
To support the always_inline function case this patch adds attribute((min_vector_width(128))) that can be used to tag these functions with their vector width. All x86 intrinsic functions that operate on vectors have been tagged with this attribute.
To support the macro case, all x86 specific builtins have also been tagged with the vector width that they require. Use of any builtin with this property will implicitly increase the min_vector_width of the function that calls it. I've done this as a new property in the attribute string for the builtin rather than basing it on the type string so that we can opt into it on a per builtin basis and avoid any impact to target independent builtins.
There will be future work to support vectors passed as function arguments and supporting inline assembly. And whatever else we can find that isn't covered by this patch.
Special thanks to Chandler who suggested this direction and reviewed a preview version of this patch. And thanks to Eric Christopher who has had many conversations with me about this issue.
Differential Revision: https://reviews.llvm.org/D48617
llvm-svn: 336583
All of these found by grepping through IR from the builtin tests for extra trunc and zext/sext instructions that shouldn't have been there.
Some of these were real bugs where we lost bits from the user input:
_mm512_mask_broadcast_f32x8
_mm512_maskz_broadcast_f32x8
_mm512_mask_broadcast_i32x8
_mm512_maskz_broadcast_i32x8
_mm256_mask_cvtusepi16_storeu_epi8
llvm-svn: 336042
I'm looking into making the select builtins require avx512f, avx512bw, or avx512vl since masking operations generally require those features.
The extract builtins are funny because the 512-bit versions return a 128 or 256 bit vector with masking even when avx512vl is not supported.
llvm-svn: 334330
Test changes are due to differences in how we generate undef elements now. We also changed the types used for extractf128_si256/insertf128_si256 to match the signature of the builtin that previously existed which this patch resurrects. This also matches gcc.
llvm-svn: 334261
This is more consistent with other usages of builtin_shufflevector. Later optimization passes or codegen will detect the duplicate vector and replace it with undef. Using _mm_undefined just puts a zeroinitializer that still needs to be optimized out later.
llvm-svn: 333944
The majority of the cases were correct. This fixes the few that weren't.
I also removed some superfluous parentheses in non-macros that confused by attempts at grepping for missing casts.
llvm-svn: 333615
I think this is a holdover from when we used to declare variables inside the macros. And then its been copy and pasted forward for years every time a new macro intrinsic gets added.
Interestingly this caused some tests for IRGen to be slightly more optimized. We now return a zeroinitializer directly instead of going through a store+load.
It also removed a bogus error message on another test.
llvm-svn: 333613
We had quite a few for different element sizes of integers sometimes with strange target features attached to them.
We only need a single version for each of _m128i, _m256i, and _m512i with the target feature that first introduced those types.
llvm-svn: 333568
I believe this is safe assuming default default FP environment. The conversion might be inexact, but it can never overflow the FP type so this shouldn't be undefined behavior for the uitofp/sitofp instructions.
We already do something similar for scalar conversions.
Differential Revision: https://reviews.llvm.org/D46863
llvm-svn: 332882
This patch implements the broadcastf32x2/broadcasti32x2 intrinsics using __builtin_shufflevector.
Differential Revision: https://reviews.llvm.org/D37287
llvm-svn: 312135
Unfortunately, the backend currently doesn't fold masks into the instructions correctly when they come from these shufflevectors. I'll work on that in a future commit.
llvm-svn: 285667
Unfortunately, the backend currently doesn't fold masks into the instructions correctly when they come from these shufflevectors. I'll work on that in a future commit.
llvm-svn: 285540
This is really only needed for addition, subtraction, and multiplication, but I did the bitwise ops too for overall consistency. Clang currently doesn't set NSW for signed vector operations so the undefined behavior shouldn't happen today.
llvm-svn: 271778
This is a mostly mechanical change accomplished with a script. I tried to split out any changes to the typecasts that already existed into separate commits.
llvm-svn: 269740
convert i64 to FP and vice versa
reduceps & reducepd
rangeps & rangepd
all in their 512bit versions
Differential Revision: http://reviews.llvm.org/D11716
llvm-svn: 247881
This involved removing the conditional inclusion and replacing them
with target attributes matching the original conditional inclusion
and checks. The testcase update removes the macro checks for each
file and replaces them with usage of the __target__ attribute, e.g.:
int __attribute__((__target__(("sse3")))) foo(int a) {
_mm_mwait(0, 0);
return 4;
}
This usage does require the enclosing function have the requisite
__target__ attribute for inlining and code generation - also for
any macro intrinsic uses in the enclosing function. There's no change
for existing uses of the intrinsic headers.
llvm-svn: 239883
Craig Topper