llvm-6502/test/CodeGen
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
..
AArch64 [aarch64] Add a test that should have been in r212242 but I forgot to 2014-07-03 02:12:26 +00:00
ARM Debug info: split out complex DIVariable address expressions into a 2014-06-30 17:17:35 +00:00
CPP
Generic
Hexagon
Inputs
Mips Print a=b as an assignment. 2014-06-24 22:45:16 +00:00
MSP430
NVPTX [NVPTX] Add reflect intrinsic (better than matching by function name) 2014-06-27 18:36:11 +00:00
PowerPC Fix ppcf128 component access on little-endian systems 2014-07-03 15:06:47 +00:00
R600 R600: Promote i64 loads to v2i32 2014-07-02 20:53:54 +00:00
SPARC
SystemZ
Thumb
Thumb2
X86 Fix ppcf128 component access on little-endian systems 2014-07-03 15:06:47 +00:00
XCore