llvm-6502/lib/Target
Chris Lattner 9413678f91 add an option to turn on LSR.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26080 91177308-0d34-0410-b5e6-96231b3b80d8
2006-02-09 05:06:36 +00:00
..
Alpha Change Select() from 2006-02-09 00:37:58 +00:00
CBackend Make the C writer work with packed types. printContainedStructs is 2006-01-20 20:43:57 +00:00
IA64 Change Select() from 2006-02-09 00:37:58 +00:00
PowerPC Change Select() from 2006-02-09 00:37:58 +00:00
Skeleton PHI and INLINEASM are now built-in instructions provided by Target.td 2006-01-27 01:46:15 +00:00
Sparc add an option to turn on LSR. 2006-02-09 05:06:36 +00:00
SparcV8 Remove the SparcV8 backend. It has been renamed to be the Sparc backend. 2006-02-05 06:33:29 +00:00
SparcV9 Adjust to MachineConstantPool interface change: instead of keeping a 2006-02-09 04:46:04 +00:00
X86 provide an explicit alignment for cp entries 2006-02-09 02:15:30 +00:00
Makefile DONT_BUILD_RELINKED is gone and implied by BUILD_ARCHIVE now 2005-10-24 02:26:13 +00:00
MRegisterInfo.cpp Finegrainify namespacification 2006-02-01 18:10:56 +00:00
README.txt This xform isn't safe 2006-02-05 08:26:16 +00:00
SubtargetFeature.cpp Improve compatibility with VC2005, patch by Morten Ofstad! 2006-01-26 20:41:32 +00:00
Target.td Subtarget feature can now set any variable to any value 2006-01-27 08:09:42 +00:00
TargetData.cpp Implement a new InvalidateStructLayoutInfo method and add some comments 2006-01-14 00:07:34 +00:00
TargetFrameInfo.cpp Eliminate all remaining tabs and trailing spaces. 2005-07-27 06:12:32 +00:00
TargetInstrInfo.cpp Convert tabs to spaces 2005-04-22 17:54:37 +00:00
TargetMachine.cpp Remove the X86 and PowerPC Simple instruction selectors; their time has 2005-08-18 23:53:15 +00:00
TargetMachineRegistry.cpp 1. Use SubtargetFeatures in llc/lli. 2005-09-01 21:38:21 +00:00
TargetSchedInfo.cpp Convert tabs to spaces 2005-04-22 17:54:37 +00:00
TargetSchedule.td Add a default NoItinerary class for targets to use. 2006-01-27 01:41:38 +00:00
TargetSelectionDAG.td Targets all now request ConstantFP to be legalized into TargetConstantFP. 2006-01-29 06:26:08 +00:00
TargetSubtarget.cpp Eliminate all remaining tabs and trailing spaces. 2005-07-27 06:12:32 +00:00

Target Independent Opportunities:

===-------------------------------------------------------------------------===

FreeBench/mason contains code like this:

static p_type m0u(p_type p) {
  int m[]={0, 8, 1, 2, 16, 5, 13, 7, 14, 9, 3, 4, 11, 12, 15, 10, 17, 6};
  p_type pu;
  pu.a = m[p.a];
  pu.b = m[p.b];
  pu.c = m[p.c];
  return pu;
}

We currently compile this into a memcpy from a static array into 'm', then
a bunch of loads from m.  It would be better to avoid the memcpy and just do
loads from the static array.

===-------------------------------------------------------------------------===

Get the C front-end to expand hypot(x,y) -> llvm.sqrt(x*x+y*y) when errno and
precision don't matter (ffastmath).  Misc/mandel will like this. :)

===-------------------------------------------------------------------------===

For all targets, not just X86:
When llvm.memcpy, llvm.memset, or llvm.memmove are lowered, they should be 
optimized to a few store instructions if the source is constant and the length
is smallish (< 8). This will greatly help some tests like Shootout/strcat.c
and fldry.

//===---------------------------------------------------------------------===//

Solve this DAG isel folding deficiency:

int X, Y;

void fn1(void)
{
  X = X | (Y << 3);
}

compiles to

fn1:
	movl Y, %eax
	shll $3, %eax
	orl X, %eax
	movl %eax, X
	ret

The problem is the store's chain operand is not the load X but rather
a TokenFactor of the load X and load Y, which prevents the folding.

There are two ways to fix this:

1. The dag combiner can start using alias analysis to realize that y/x
   don't alias, making the store to X not dependent on the load from Y.
2. The generated isel could be made smarter in the case it can't
   disambiguate the pointers.

Number 1 is the preferred solution.

//===---------------------------------------------------------------------===//