llvm/lib
Ulrich Weigand 1ef2cec146 Fix ppcf128 component access on little-endian systems
The PowerPC 128-bit long double data type (ppcf128 in LLVM) is in fact a
pair of two doubles, where one is considered the "high" or
more-significant part, and the other is considered the "low" or
less-significant part.  When a ppcf128 value is stored in memory or a
register pair, the high part always comes first, i.e. at the lower
memory address or in the lower-numbered register, and the low part
always comes second.  This is true both on big-endian and little-endian
PowerPC systems.  (Similar to how with a complex number, the real part
always comes first and the imaginary part second, no matter the byte
order of the system.)

This was implemented incorrectly for little-endian systems in LLVM.
This commit fixes three related issues:

- When printing an immediate ppcf128 constant to assembler output
  in emitGlobalConstantFP, emit the high part first on both big-
  and little-endian systems.

- When lowering a ppcf128 type to a pair of f64 types in SelectionDAG
  (which is used e.g. when generating code to load an argument into a
  register pair), use correct low/high part ordering on little-endian
  systems.

- In a related issue, because lowering ppcf128 into a pair of f64 must
  operate differently from lowering an int128 into a pair of i64,
  bitcasts between ppcf128 and int128 must not be optimized away by the
  DAG combiner on little-endian systems, but must effect a word-swap.

Reviewed by Hal Finkel.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212274 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-03 15:06:47 +00:00
..
Analysis Add new lines to debugging information. 2014-07-03 02:11:49 +00:00
AsmParser IR: Add COMDATs to the IR 2014-06-27 18:19:56 +00:00
Bitcode IR: Add COMDATs to the IR 2014-06-27 18:19:56 +00:00
CodeGen Fix ppcf128 component access on little-endian systems 2014-07-03 15:06:47 +00:00
DebugInfo Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
ExecutionEngine ExecutionEngine::create(): fix interpreter fallback when JIT is unavailable 2014-07-01 03:18:49 +00:00
IR Fix typos. 2014-07-02 22:05:40 +00:00
IRReader IRReader: don't mark MemoryBuffers const 2014-06-27 09:19:14 +00:00
LineEditor
Linker Include <tuple> to make buildbots happy 2014-06-27 18:38:12 +00:00
LTO Use a range loop. No functionality change. 2014-06-28 18:44:59 +00:00
MC Invert the MC -> Object dependency. 2014-07-03 02:01:39 +00:00
Object Invert the MC -> Object dependency. 2014-07-03 02:01:39 +00:00
Option Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
ProfileData Renaming SwapByteOrder() to getSwappedBytes() 2014-06-14 11:36:01 +00:00
Support Remove obsolete function TargetRegistry::getClosestTargetForJIT() 2014-07-01 10:47:13 +00:00
TableGen Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
Target [x86] Fix crashes in lowering bitcast instructions with the widening 2014-07-03 03:43:47 +00:00
Transforms [msan] Stop propagating shadow in blacklisted functions. 2014-07-03 11:56:30 +00:00
CMakeLists.txt
LLVMBuild.txt
Makefile