hanchenye-llvm-project/llvm
Sanjay Patel 3d497cd778 Improve sqrt estimate algorithm (fast-math)
This patch changes the fast-math implementation for calculating sqrt(x) from:
y = 1 / (1 / sqrt(x))
to:
y = x * (1 / sqrt(x))

This has 2 benefits: less code / faster code and one less estimate instruction 
that may lose precision.

The only target that will be affected (until http://reviews.llvm.org/D5658 is approved)
is PPC. The difference in codegen for PPC is 2 less flops for a single-precision sqrtf
or vector sqrtf and 4 less flops for a double-precision sqrt. 
We also eliminate a constant load and extra register usage.

Differential Revision: http://reviews.llvm.org/D5682

llvm-svn: 219445
2014-10-09 21:26:35 +00:00
..
autoconf Recognize aarch64_be as valid architecture. 2014-10-06 23:05:04 +00:00
bindings
cmake Revert r219354. It seems to break some buildbots. 2014-10-08 23:07:59 +00:00
docs Update dwarf::ApplePropertyAttributes enum to meaningful values. 2014-10-08 14:59:44 +00:00
examples Add doInitialization/doFinalization to DataLayoutPass. 2014-09-10 21:27:43 +00:00
include Add ApplePropertyString dump helper to Dwarf.{h|cpp}. 2014-10-09 20:43:04 +00:00
lib Improve sqrt estimate algorithm (fast-math) 2014-10-09 21:26:35 +00:00
projects
test Improve sqrt estimate algorithm (fast-math) 2014-10-09 21:26:35 +00:00
tools Object: Add range iterators for COFF import/export table 2014-10-09 02:16:38 +00:00
unittests [Support] Add MemoryBuffer::getFileSlice() 2014-10-08 00:22:18 +00:00
utils [AVX512] Extended avx512_binop_rm for AVX512VL subsets. 2014-10-09 08:38:48 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore
CMakeLists.txt Add LLVM_ENABLE_MODULES flag to CMake to enable building with C++ modules. 2014-09-26 22:40:15 +00:00
CODE_OWNERS.TXT Add Tom Stellard's role as 3.5 release manager. 2014-09-12 08:07:31 +00:00
CREDITS.TXT
LICENSE.TXT
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in Remove unused ALL_BINDINGS configuration variable. 2014-10-03 23:03:01 +00:00
Makefile.rules Revert my earlier change to add "all" as a dependency to check. In 2014-09-19 18:44:27 +00:00
README.txt
configure Remove unused ALL_BINDINGS configuration variable. 2014-10-03 23:03:01 +00:00
llvm.spec.in

README.txt

Low Level Virtual Machine (LLVM)
================================

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