Bruno Cardoso Lopes ba059464c3 [x86] Add vector @llvm.ctpop intrinsic custom lowering ... Currently, when ctpop is supported for scalar types, the expansion of @llvm.ctpop.vXiY uses vector element extractions, insertions and individual calls to @llvm.ctpop.iY. When not, expansion with bit-math operations is used for the scalar calls. Local haswell measurements show that we can improve vector @llvm.ctpop.vXiY expansion in some cases by using a using a vector parallel bit twiddling approach, based on: v = v - ((v >> 1) & 0x55555555); v = (v & 0x33333333) + ((v >> 2) & 0x33333333); v = ((v + (v >> 4) & 0xF0F0F0F) v = v + (v >> 8) v = v + (v >> 16) v = v & 0x0000003F (from http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel) When scalar ctpop isn't supported, the approach above performs better for v2i64, v4i32, v4i64 and v8i32 (see numbers below). And even when scalar ctpop is supported, this approach performs ~2x better for v8i32. Here, x86_64 implies -march=corei7-avx without ctpop and x86_64h includes ctpop support with -march=core-avx2. == [x86_64h - new] v8i32: 0.661685 v4i32: 0.514678 v4i64: 0.652009 v2i64: 0.324289 == [x86_64h - old] v8i32: 1.29578 v4i32: 0.528807 v4i64: 0.65981 v2i64: 0.330707 == [x86_64 - new] v8i32: 1.003 v4i32: 0.656273 v4i64: 1.11711 v2i64: 0.754064 == [x86_64 - old] v8i32: 2.34886 v4i32: 1.72053 v4i64: 1.41086 v2i64: 1.0244 More work for other vector types will come next. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224725 91177308-0d34-0410-b5e6-96231b3b80d8		2014-12-22 19:45:43 +00:00
..
Analysis	InstSimplify: Don't bother if getScalarSizeInBits returns zero	2014-12-20 04:45:33 +00:00
AsmParser	IR: Make metadata typeless in assembly	2014-12-15 19:07:53 +00:00
Bitcode	Fix Visual C++ error "'llvm::make_unique' : ambiguous call to overloaded function".	2014-12-18 10:03:35 +00:00
CodeGen	[CodeGenPrepare] Handle properly the promotion of operands when this does not	2014-12-22 18:11:52 +00:00
DebugInfo	[DebugInfo] Move all DWARF headers to the public include directory.	2014-12-19 18:26:33 +00:00
ExecutionEngine	[C API] Expose LLVMGetGlobalValueAddress and LLVMGetFunctionAddress.	2014-12-22 18:53:11 +00:00
IR	The leak detector is dead, long live asan and valgrind.	2014-12-22 13:00:36 +00:00
IRReader
LineEditor
Linker	Rename MapValue(Metadata*) to MapMetadata()	2014-12-19 06:06:18 +00:00
LTO	LTO: Lazy-load LTOModule in local contexts	2014-12-17 22:05:42 +00:00
MC	Remove unused header. NFC.	2014-12-22 19:09:15 +00:00
Object	Add printing the LC_ROUTINES load commands with llvm-objdump’s -private-headers.	2014-12-19 22:25:22 +00:00
Option
ProfileData
Support	Add missing implementation of 'sys::path::is_other' to the support library.	2014-12-18 18:19:47 +00:00
TableGen	Clean up static analyzer warnings.	2014-12-12 21:48:03 +00:00
Target	[x86] Add vector @llvm.ctpop intrinsic custom lowering	2014-12-22 19:45:43 +00:00
Transforms	InstCombine: Squash an icmp+select into bitwise arithmetic	2014-12-20 04:45:35 +00:00
CMakeLists.txt
LLVMBuild.txt
Makefile