This patch will optimize the following cases:
  sub r1, r3 | sub r1, imm
  cmp r3, r1 or cmp r1, r3 | cmp r1, imm
  bge L1

TO
  subs r1, r3
  bge  L1 or ble L1

If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.

rdar: 10734411
llvm-svn: 156599

but it generates int3 on x86 instead of ud2.

llvm-svn: 156593

to user only read/write.

Part of rdar://11325849

llvm-svn: 156591

llvm-svn: 156589

The sub-registers explicitly listed in SubRegs in the .td files form a
tree. In a complicated register bank, it is possible to have
sub-register relationships across sub-trees. For example, the ARM NEON
double vector Q0_Q1 is a tree:

  Q0_Q1 = [Q0, Q1],  Q0 = [D0, D1], Q1 = [D2, D3]

But we also define the DPair register D1_D2 = [D1, D2] which is fully
contained in Q0_Q1.

This patch teaches TableGen to find such sub-register relationships, and
assign sub-register indices to them. In the example, TableGen will
create a dsub_1_dsub_2 sub-register index, and add D1_D2 as a
sub-register of Q0_Q1.

This will eventually enable the coalescer to handle copies of skewed
sub-registers.

llvm-svn: 156587

add an additional parameter to InstCombiner::EmitGEPOffset() to force it to *not* emit operations with NUW flag

llvm-svn: 156585

llvm-svn: 156579

Patch by Jack Carter.

llvm-svn: 156577

llvm-svn: 156576

llvm-svn: 156575

Prioritize the instruction that comes closest to keeping pressure
under the target's limit. Then prioritize instructions that avoid
increasing the max pressure in the scheduled region. The max pressure
heuristic is a tad aggressive. Later I'll fix it to consider the
unscheduled pressure as well.

WIP: This is mostly functional but untested and not likely to do much good yet.
llvm-svn: 156574

llvm-svn: 156573

llvm-svn: 156572

llvm-svn: 156571

llvm-svn: 156569

llvm-svn: 156568

Added getMaxExcessUpward/DownwardPressure. They somewhat abuse the
tracker by speculatively handling an instruction out of order. But it
is convenient for now. In the future, we will cache each instruction's
pressure contribution to make this efficient.

llvm-svn: 156561

llvm-svn: 156560

llvm-svn: 156558

This commit broke an external linux bot and gave a compile-time warning.

llvm-svn: 156556

The .td files specify a tree of sub-registers. Store that tree as
ExplicitSubRegs lists in CodeGenRegister instead of extracting it from
the Record when needed.

llvm-svn: 156555

of recursion, to avoid excessive stack usage on deep expressions.

llvm-svn: 156554

llvm-svn: 156553

llvm-svn: 156551

This patch will optimize the following cases:
  sub r1, r3 | sub r1, imm
  cmp r3, r1 or cmp r1, r3 | cmp r1, imm
  bge L1

TO
  subs r1, r3
  bge  L1 or ble L1

If the branch instruction can use flag from "sub", then we can replace
"sub" with "subs" and eliminate the "cmp" instruction.

rdar: 10734411
llvm-svn: 156550

Instruction::IsIdenticalToWhenDefined.

This manifested itself when inlining two calls to the same function.  The 
inlined function had a switch statement that returned one of a set of 
global variables.  Without this modification, the two phi instructions that 
chose values from the branches of the switch instruction inlined from the 
callee were considered equivalent and jump-threading replaced a load for the 
first switch value with a phi selecting from the second switch, thereby 
producing incorrect code.

This patch has been tested with "make check-all", "lnt runteste nt", and 
llvm self-hosted, and on the original program that had this problem, 
wireshark.

<rdar://problem/11025519>

llvm-svn: 156548

llvm-svn: 156541

llvm-svn: 156540

Starting r155461 we are able to select patterns for vbroadcast even when the load op is used by other users.

Fix PR11900.

llvm-svn: 156539

I initially assumed that the subreg graph was a tree. That may not be true.

llvm-svn: 156524

Patch by Yury Mikhaylov <yury.mikhaylov@gmail.com>.

llvm-svn: 156523

llvm-svn: 156521

end of a basic block if there's no store.

llvm-svn: 156520

This mapping is for internal use by TableGen. It will not be exposed in
the generated files.

Unfortunately, the mapping is not completely well-defined. The X86 xmm
registers appear with multiple sub-register indices in the ymm
registers. This is because of the odd idempotent sub_sd and sub_ss
sub-register indices. I hope to be able to eliminate them entirely, so
we can require the sub-registers to form a tree.

For now, just place the canonical sub_xmm index in the mapping, and
ignore the idempotents.

llvm-svn: 156519

That's what it does.

llvm-svn: 156518

refactor code a bit to enable future changes to support run-time information
add support to compute allocation sizes at run-time if penalty > 1 (e.g., malloc(x), calloc(x, y), and VLAs)

llvm-svn: 156515

llvm-svn: 156507

This bug was fixed by Jim Grosbach in #138879, thanks Jim!

llvm-svn: 156505

llvm-svn: 156494

llvm-svn: 156492