unsigned test(unsigned a) {
  return ~a;
}
llvm used to generate:
movl    $4294967295, %eax
xorl    4(%esp), %eax

Now it generates:
movl      4(%esp), %eax
notl      %eax

It's 3 bytes shorter.

llvm-svn: 62661

to Eli for pointing out that these forms don't ignore the high bits of
their index operands, and as such are not immediately suitable for use
by isel.

llvm-svn: 62194

llvm-svn: 62180

llvm-svn: 62179

into their left operand, rather than their right. Do this
by commuting the operands and inverting the condition.

llvm-svn: 61842

llvm-svn: 61836

X86_COND_B and X86_COND_AE, respectively.

llvm-svn: 61835

Do not isel load folding bt instructions for pentium m, core, core2, and AMD processors. These are significantly slower than a load followed by a bt of a register.

llvm-svn: 61557

llvm-svn: 61425

llvm-svn: 61424

llvm-svn: 61400

  which are identical to the original patterns.

- Change the multiply with overflow so that we distinguish between signed and
  unsigned multiplication. Currently, unsigned multiplication with overflow
  isn't working!

llvm-svn: 60963

ISD::ADD to emit an implicit EFLAGS. This was horribly broken. Instead, replace
the intrinsic with an ISD::SADDO node. Then custom lower that into an
X86ISD::ADD node with a associated SETCC that checks the correct condition code
(overflow or carry). Then that gets lowered into the correct X86::ADDOvf
instruction.

Similar for SUB and MUL instructions.

llvm-svn: 60915

target-independent way of determining overflow on multiplication. It's very
tricky. Patch by Zoltan Varga!

llvm-svn: 60800

llvm-svn: 60651

llvm-svn: 60487

llvm-svn: 60385

llvm-svn: 60383

- Add support for seto, setno, setc, and setnc instructions.

llvm-svn: 60382

the conditional for the BRCOND statement. For instance, it will generate:

    addl %eax, %ecx
    jo LOF

instead of

    addl %eax, %ecx
    ; About 10 instructions to compare the signs of LHS, RHS, and sum.
    jl LOF

llvm-svn: 60123

they trap on divide-by-zero, and this side effect is otherwise
unmodeled.

llvm-svn: 59551

llvm-svn: 58141

Add implicit defs of XMM8 to XMM15 on 32-bit call instructions. While this is not technically true, it tells tblgen that these instructions "clobber" the entire XMM register file.

llvm-svn: 57723

use a SUB instruction instead of an ADD, because -128 can be
encoded in an 8-bit signed immediate field, while +128 can't be.
This avoids the need for a 32-bit immediate field in this case.

A similar optimization applies to 64-bit adds with 0x80000000,
with the 32-bit signed immediate field.

To support this, teach tablegen how to handle 64-bit constants.

llvm-svn: 57663

shift counts, and patterns that match dynamic shift counts
when the subtract is obscured by a truncate node.

Add DAGCombiner support for recognizing rotate patterns
when the shift counts are defined by truncate nodes.

Fix and simplify the code for commuting shld and shrd
instructions to work even when the given instruction doesn't
have a parent, and when the caller needs a new instruction.

These changes allow LLVM to use the shld, shrd, rol, and ror
instructions on x86 to replace equivalent code using two
shifts and an or in many more cases.

llvm-svn: 57662

the predicates by extending simple predicates to create
more complex predicates instead of duplicating the logic
for the simple predicates.

This doesn't reduce much redundancy in DAGISelEmitter.cpp's
generated source yet; that will require improvements to
DAGISelEmitter.cpp's instruction sorting, to make it more
effectively group nodes with similar predicates together.

llvm-svn: 57565

parameters instead of raw Constants.  This prevents the constants from
being selected by the isel pass, fixing PR2735.

llvm-svn: 57385

Fixes local RA miscompilation of gcc.c-torture/execute/20020904-1.c -O0.

llvm-svn: 57257

Make it all work in non-pic mode.

llvm-svn: 57034

incidentally making the case where the memop is a
pointer deref work.  Fix cmp-and-swap regression.

llvm-svn: 57027

llvm-svn: 56963

This allows the 64-bit forms to use+def RSP instead of ESP. This
doesn't fix any real bugs today, but it is more precise and it
makes the debug dumps on x86-64 look more consistent.

Also, add some comments describing the CALL instructions' physreg
operand uses and defs.

llvm-svn: 56925

llvm-svn: 56911

llvm-svn: 56792

Implement "punpckldq  %xmm0, $xmm0" as "pshufd  $0x50, %xmm0, %xmm" unless optimizing for code size.

llvm-svn: 56711

Fix patterns for SSE4.1 move and sign extend instructions. Also add instructions which fold VZEXT_MOVL and VZEXT_LOAD.

llvm-svn: 56594

Apologies for the thrashing.

llvm-svn: 56251

- Add linkage to SymbolSDNode (default to external).
- Change ISD::ExternalSymbol to ISD::Symbol.
- Change ISD::TargetExternalSymbol to ISD::TargetSymbol

These changes pave the way to allowing SymbolSDNodes with non-external linkage.

llvm-svn: 56249

with ConstantInt. This led to fixing a bug in TargetLowering.cpp
using getValue instead of getAPIntValue.

llvm-svn: 56159

Transform (x << (y&31)) -> (x << y). This takes advantage of the fact x86 shift instructions 2nd operand (shift count) is limited to 0 to 31 (or 63 in the x86-64 case).

llvm-svn: 55558