llvm-svn: 113666

the 'zero' bit down into the back-end. There are other cases where this logic
isn't sufficient, so they should be handled separately.

llvm-svn: 113665

iterator when an optimization took place. This allows us to do more insane
things with the code than just remove an instruction or two.

llvm-svn: 113640

llvm-svn: 112287

a register before checking if it was defined.

llvm-svn: 110733

llvm-svn: 110726

ARM testers.

llvm-svn: 110718

pass. This pass should expand with all of the small, fine-grained optimization
passes to reduce compile time and increase happiment.

llvm-svn: 110627

llvm-svn: 110460

llvm-svn: 110410

ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396

llvm-svn: 110069

llvm-svn: 109045

EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

llvm-svn: 107879

   %reg1025 = <sext> %reg1024
    ...
   %reg1026 = SUBREG_TO_REG 0, %reg1024, 4

into this:

   %reg1025 = <sext> %reg1024
    ...
   %reg1027 = EXTRACT_SUBREG %reg1025, 4
   %reg1026 = SUBREG_TO_REG 0, %reg1027, 4

The problem here is that SUBREG_TO_REG is there to assert that an implicit zext
occurs. It doesn't insert a zext instruction. If we allow the EXTRACT_SUBREG
here, it will give us the value after the <sext>, not the original value of
%reg1024 before <sext>.

llvm-svn: 105741

llvm-svn: 99573

into TargetOpcodes.h.  #include the new TargetOpcodes.h
into MachineInstr.  Add new inline accessors (like isPHI())
to MachineInstr, and start using them throughout the 
codebase.

llvm-svn: 95687

Do not extend extension results beyond the use of a PHI instruction at the start of a use block. A PHI use is expected to kill its source values.

llvm-svn: 93895

Commit some changes I had managed to lose last night while refactoring the code. Avoid change use of PHI instructions because it's not legal to insert any instructions before them.
This fixes PR6027.

llvm-svn: 93335

llvm-svn: 93306

Add a quick pass to optimize sign / zero extension instructions. For targets where the pre-extension values are available in the subreg of the result of the extension, replace the uses of the pre-extension value with the result + extract_subreg.

For now, this pass is fairly conservative. It only perform the replacement when both the pre- and post- extension values are used in the block. It will miss cases where the post-extension values are live, but not used.

llvm-svn: 93278