Commit Graph

8 Commits

Author SHA1 Message Date
Andrea Di Biagio c9649eb9da [X86][BtVer2] Fix latency/throughput of scalar integer MUL instructions.
Single operand MUL instructions that implicitly set EAX have the following
latency/throughput profile (see below):

imul %cl              # latency: 3cy - uOPs: 1 - 1 JMul
imul %cx              # latency: 3cy - uOPs: 3 - 3 JMul
imul %ecx             # latency: 3cy - uOPs: 2 - 2 JMul
imul %rcx             # latency: 6cy - uOPs: 2 - 4 JMul

mul %cl               # latency: 3cy - uOPs: 1 - 1 JMul
mul %cx               # latency: 3cy - uOPs: 3 - 3 JMul
mul %ecx              # latency: 3cy - uOPs: 2 - 2 JMul
mul %rcx              # latency: 6cy - uOPs: 2 - 4 JMul

Excluding the 64bit variant, which has a latency of 6cy, every other instruction
has a latency of 3cy. However, the number of decoded macro-opcodes (as well as
the resource cyles) depend on the MUL size.

The two operand MULs have a more predictable profile (see below):

imul %dx, %dx         # latency: 3cy - uOPs: 1 - 1 JMul
imul %edx, %edx       # latency: 3cy - uOPs: 1 - 1 JMul
imul %rdx, %rdx       # latency: 6cy - uOPs: 1 - 4 JMul

imul $3, %dx, %dx     # latency: 4cy - uOPs: 2 - 2 JMul
imul $3, %ecx, %ecx   # latency: 3cy - uOPs: 1 - 1 JMul
imul $3, %rdx, %rdx   # latency: 6cy - uOPs: 1 - 4 JMul

This patch updates the values in the Jaguar scheduling model and regenerates
llvm-mca tests.

Differential Revision: https://reviews.llvm.org/D66547

llvm-svn: 369661
2019-08-22 15:20:16 +00:00
Reid Kleckner 953bdce68d [MC] Separate masm integer literal lexer support from inline asm
Summary:
This renames the IsParsingMSInlineAsm member variable of AsmLexer to
LexMasmIntegers and moves it up to MCAsmLexer. This is the only behavior
controlled by that variable. I added a public setter, so that it can be
set from outside or from the llvm-mc command line. We may need to
arrange things so that users can get this behavior from clang, but
that's future work.

I also put additional hex literal lexing functionality under this flag
to fix PR32973. It appears that this hex literal parsing wasn't intended
to be enabled in non-masm-style blocks.

Now, masm integers (0b1101 and 0ABCh) work in __asm blocks from clang,
but 0b label references work when using .intel_syntax in standalone .s
files.

However, 0b label references will *not* work from __asm blocks in clang.
They will work from GCC inline asm blocks, which it sounds like is
important for Crypto++ as mentioned in PR36144.

Essentially, we only lex masm literals for inline asm blobs that use
intel syntax. If the .intel_syntax directive is used inside a gnu-style
inline asm statement, masm literals will not be lexed, which is
compatible with gas and llvm-mc standalone .s assembly.

This fixes PR36144 and PR32973.

Reviewers: Gerolf, avt77

Subscribers: eraman, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D53535

llvm-svn: 345189
2018-10-24 20:23:57 +00:00
Andrea Di Biagio a2eee47450 [llvm-mca] Add fields "Total uOps" and "uOps Per Cycle" to the report generated by the SummaryView.
This patch adds two new fields to the perf report generated by the SummaryView.
Fields are now logically organized into two small groups; only the second group
contains throughput indicators.

Example:
```
Iterations:        100
Instructions:      300
Total Cycles:      414
Total uOps:        700

Dispatch Width:    4
uOps Per Cycle:    1.69
IPC:               0.72
Block RThroughput: 4.0
```

This patch also updates the docs for llvm-mca.
Due to the nature of this change, several tests in the tools/llvm-mca directory
were affected, and had to be updated using script `update_mca_test_checks.py`.

llvm-svn: 340946
2018-08-29 17:56:39 +00:00
Andrea Di Biagio f84b0a6914 [llvm-mca] Regenerate X86 specific tests. NFC
Not all tests were correctly updated by the update script after r336797.

llvm-svn: 337124
2018-07-15 11:43:11 +00:00
Roman Lebedev 7b53d1454f [llvm-mca] Make sure not to end the test files with an empty line.
Summary:
It's super irritating.

[properly configured] git client then complains about that double-newline,
and you have to use `--force` to ignore the warning, since even if you
fix it manually, it will be reintroduced the very next runtime :/

Reviewers: RKSimon, andreadb, courbet, craig.topper, javed.absar, gbedwell

Reviewed By: gbedwell

Subscribers: javed.absar, tschuett, gbedwell, llvm-commits

Differential Revision: https://reviews.llvm.org/D47697

llvm-svn: 333887
2018-06-04 11:48:46 +00:00
Greg Bedwell e790f6fb06 [UpdateTestChecks] Improved update_mca_test_checks block analysis
Previously update_mca_test_checks worked entirely at "block" level where
a block is some sequence of lines delimited by at least one empty line.
This generally worked well, but could sometimes lead to excessive
repetition of check lines for various prefixes if some block was almost
identical between prefixes, but not quite (for example, due to a
different dispatch width in the otherwise identical summary views).

This new analyis attempts to split blocks further in the case where the
following conditions are met:
  a) There is some prefix common to every RUN line (typically 'ALL').
  b) The first line of the block is common to the output with every prefix.
  c) The block has the same number of lines for the output with every prefix.

Also, regenerated all llvm-mca test files with the following command:
update_mca_test_checks.py "../test/tools/llvm-mca/*/*.s" "../test/tools/llvm-mca/*/*/*.s"

The new analysis showed a "multiple lines not disambiguated by prefixes" warning
for test "AArch64/Exynos/scheduler-queue-usage.s" so I've also added some
explicit prefixes to each of the RUN lines in that test.

Differential Revision: https://reviews.llvm.org/D47321

llvm-svn: 333204
2018-05-24 16:36:44 +00:00
Andrea Di Biagio cb1ed400a4 [llvm-mca] Removed an empty line generated by the timeline view. NFC.
Also, regenerate all tests.

llvm-svn: 332853
2018-05-21 17:11:56 +00:00
Andrea Di Biagio 0626864fa4 [llvm-mca] Default the output asm dialect used by the instruction printer to the input asm dialect.
The instruction printer used by llvm-mca to generate the performance report now
defaults the output assembly format to the format used for the input assembly
file.

On x86, the asm format can be either AT&T or Intel, depending on the
presence/absence of directive `.intel_syntax`.

Users can still specify a different assembly dialect with the command line flag
-output-asm-variant=<uint>.

llvm-svn: 330733
2018-04-24 16:19:08 +00:00