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Daniel Sanders 059e4b158c [mips][fp64] Add an implicit def to MFHC1 claiming that it reads the lower 32-bits of 64-bit FPR
Summary:
This is a white lie to workaround a widespread bug in the -mfp64
implementation.

The problem is that none of the 32-bit fpu ops mention the fact that they
clobber the upper 32-bits of the 64-bit FPR. This allows MFHC1 to be
scheduled on the wrong side of most 32-bit FPU ops. Fixing that requires a
major overhaul of the FPU implementation which can't be done right now due to
time constraints.

MFHC1 is one of two affected instructions. These instructions are the only
FPU instructions that don't read or write the lower 32-bits. We therefore
pretend that it reads the bottom 32-bits to artificially create a dependency and
prevent the scheduler changing the behaviour of the code.
The other instruction is MTHC1 which will be fixed once I've have found a failing
test case for it. 

The testcase is test-suite/SingleSource/UnitTests/Vector/simple.c when
given TARGET_CFLAGS="-mips32r2 -mfp64 -mmsa".

Reviewers: jacksprat, matheusalmeida

Reviewed By: jacksprat

Differential Revision: http://llvm-reviews.chandlerc.com/D2966

llvm-svn: 203464
2014-03-10 15:01:57 +00:00
clang Reverting llvm::distance changes to use std::distance with iterators instead, per post-commit review feedback. 2014-03-10 13:43:55 +00:00
clang-tools-extra Use DiagnosticRenderer to convert clang diagnostics to clang-tidy ones. 2014-03-10 13:11:17 +00:00
compiler-rt ARM: fix file's header comment 2014-03-07 14:56:29 +00:00
debuginfo-tests Revert "Experimentally enable --verify-debug-info on some testcases and see if" 2014-03-08 02:46:36 +00:00
libclc Fix build since r202052 2014-02-24 21:31:56 +00:00
libcxx Fix bug I introduced (enabling implicit conversions from compare function to map) in r202994. Thanks to Sebastian Redl for the catch. 2014-03-10 04:50:10 +00:00
libcxxabi Demangle Dc to decltype(auto) as per the Itanium C++ ABI spec. 2014-02-17 21:56:01 +00:00
lld [Mips] Fix addendum reading for R_MIPS_26 relocation. 2014-03-09 13:20:01 +00:00
lldb Update LLDB for LLVM iterator change in r203364 2014-03-10 14:23:10 +00:00
llvm [mips][fp64] Add an implicit def to MFHC1 claiming that it reads the lower 32-bits of 64-bit FPR 2014-03-10 15:01:57 +00:00
openmp Revert commit (testing commit hook). 2014-03-04 18:06:04 +00:00
polly Update isl to ensure 'extern "C" {' is available 2014-03-10 13:46:52 +00:00