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Dan Gohman 281881b8e2 Optimized FCMP_OEQ and FCMP_UNE for x86.
Where previously LLVM might emit code like this:

        ucomisd %xmm1, %xmm0
        setne   %al
        setp    %cl
        orb     %al, %cl
        jne     .LBB4_2

it now emits this:

        ucomisd %xmm1, %xmm0
        jne     .LBB4_2
        jp      .LBB4_2

It has fewer instructions and uses fewer registers, but it does
have more branches. And in the case that this code is followed by
a non-fallthrough edge, it may be followed by a jmp instruction,
resulting in three branch instructions in sequence. Some effort
is made to avoid this situation.

To achieve this, X86ISelLowering.cpp now recognizes FCMP_OEQ and
FCMP_UNE in lowered form, and replace them with code that emits
two branches, except in the case where it would require converting
a fall-through edge to an explicit branch.

Also, X86InstrInfo.cpp's branch analysis and transform code now
knows now to handle blocks with multiple conditional branches. It
uses loops instead of having fixed checks for up to two
instructions. It can now analyze and transform code generated
from FCMP_OEQ and FCMP_UNE.

llvm-svn: 57873
2008-10-21 03:29:32 +00:00
autoconf Fix configure issue where configure 2008-10-07 22:21:03 +00:00
bindings PR2731: C and Ocaml bindings for setTailCall and isTailCall. 2008-08-30 16:34:54 +00:00
cmake CMake: Builds all targets. 2008-09-26 04:40:32 +00:00
docs Fix spelling error. 2008-10-20 08:45:34 +00:00
examples CMake: Builds all examples. Corrected name of CBackend target. 2008-09-26 19:48:03 +00:00
include Add skeleton for the pre-register allocation live interval splitting pass. 2008-10-20 21:44:59 +00:00
lib Optimized FCMP_OEQ and FCMP_UNE for x86. 2008-10-21 03:29:32 +00:00
projects Add "sample" documentation to sample project. 2008-09-15 05:31:29 +00:00
runtime Fixing the stack walker. 2008-01-24 05:16:36 +00:00
test Optimized FCMP_OEQ and FCMP_UNE for x86. 2008-10-21 03:29:32 +00:00
tools Re-apply Makefile changes. Fix build with srcdir != objdir. 2008-10-16 14:02:29 +00:00
utils Add RCBarriers to TargetInstrDesc. It's a list of register classes the given instruction can "clobber". For example, on x86 the call instruction can modify all of the XMM and fp stack registers. 2008-10-17 21:00:09 +00:00
website Prepare for "core" website. 2007-08-03 05:43:35 +00:00
win32 update win32 project file, patch provided by OvermindDL1 on llvmdev. 2008-10-11 22:14:59 +00:00
Xcode Remove Stacker.html from Xcode project. 2008-10-14 23:23:59 +00:00
build-for-llvm-top.sh Allow the configure options to be set according to the llvm-top options. 2007-08-31 19:53:42 +00:00
CMakeLists.txt Fun x86 encoding tricks: when adding an immediate value of 128, 2008-10-17 01:33:43 +00:00
configure Fix configure issue where configure 2008-10-07 22:21:03 +00:00
CREDITS.TXT Add another description to my entry. 2008-08-28 23:16:37 +00:00
LICENSE.TXT llvmc doesn't exist anymore, and llvmc2 doesn't have a special license file. 2008-06-20 20:05:57 +00:00
llvm.spec.in
Makefile Add support for Canadian Cross builds where the host executables are not 2008-10-02 22:56:44 +00:00
Makefile.common remove attributions from the rest of the llvm makefiles. 2007-12-29 20:11:13 +00:00
Makefile.config.in Add support for Canadian Cross builds where the host executables are not 2008-10-02 22:56:44 +00:00
Makefile.rules Fun x86 encoding tricks: when adding an immediate value of 128, 2008-10-17 01:33:43 +00:00
ModuleInfo.txt Update to include clean and install commands. 2007-07-20 20:54:41 +00:00
README.txt Remove extra lines 2008-07-28 20:50:25 +00:00

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