Machine CSE and other optimizations can remove instructions so folding
is possible at peephole while not possible at ISel.
rdar://10554090 and rdar://11873276
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160919 91177308-0d34-0410-b5e6-96231b3b80d8
It is possible that an instruction can use and update EFLAGS.
When checking the safety, we should check the usage of EFLAGS first before
declaring it is safe to optimize due to the update.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160912 91177308-0d34-0410-b5e6-96231b3b80d8
A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160893 91177308-0d34-0410-b5e6-96231b3b80d8
This option replaces the existing live interval computation with one
based on LiveRangeCalc.cpp. The new algorithm does not depend on
LiveVariables, and it can be run at any time, before or after leaving
SSA form.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160892 91177308-0d34-0410-b5e6-96231b3b80d8
This can happen as long as the instruction is not reachable. Instcombine does generate these unreachable malformed selects when doing RAUW
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160874 91177308-0d34-0410-b5e6-96231b3b80d8
The rationale here is that it's hard to write loops containing vector erases and
it only shows up if the vector contains non-trivial objects leading to crashes
when forming them out of garbage memory.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160854 91177308-0d34-0410-b5e6-96231b3b80d8
These tables were indexed by [register][subreg index] which made them,
very large and sparse.
Replace them with lists of sub-register indexes that match the existing
lists of sub-registers. MCRI::getSubReg() becomes a very short linear
search, like getSubRegIndex() already was.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160843 91177308-0d34-0410-b5e6-96231b3b80d8
Now that the weird X86 sub_ss and sub_sd sub-register indexes are gone,
there is no longer a need for the CompositeIndices construct in .td
files. Sub-register index composition can be specified on the
SubRegIndex itself using the ComposedOf field.
Also enforce unique names for sub-registers in TableGen. The same
sub-register cannot be available with multiple sub-register indexes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160842 91177308-0d34-0410-b5e6-96231b3b80d8
replace uses of function getMaxCallFrameSize defined in MipsFunctionInfo with
the one MachineFrameInfo has.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160841 91177308-0d34-0410-b5e6-96231b3b80d8
The (COPY_TO_REGCLASS GR32:$src, VR128) pattern looks odd, but
copyPhysReg does the right thing with it. (The old pattern would
eventually produce the same cross-class copy).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160830 91177308-0d34-0410-b5e6-96231b3b80d8
The SUBREG_TO_REG instruction has magic semantics asserting that the
source value was defined by an instruction that cleared the high half of
the register. Those semantics are never actually exploited for xmm
registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160818 91177308-0d34-0410-b5e6-96231b3b80d8
These idempotent sub-register indices don't do anything --- They simply
map XMM registers to themselves. They no longer affect register classes
either since the SubRegClasses field has been removed from Target.td.
This patch replaces XMM->XMM EXTRACT_SUBREG and INSERT_SUBREG patterns
with COPY_TO_REGCLASS patterns which simply become COPY instructions.
The number of IMPLICIT_DEF instructions before register allocation is
reduced, and that is the cause of the test case changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160816 91177308-0d34-0410-b5e6-96231b3b80d8
Function names should be camel case, and start with a lower case letter. No
functional change intended.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160813 91177308-0d34-0410-b5e6-96231b3b80d8
This is still a work in progress.
Out-of-order CPUs usually execute instructions from multiple basic
blocks simultaneously, so it is necessary to look at longer traces when
estimating the performance effects of code transformations.
The MachineTraceMetrics analysis will pick a typical trace through a
given basic block and provide performance metrics for the trace. Metrics
will include:
- Instruction count through the trace.
- Issue count per functional unit.
- Critical path length, and per-instruction 'slack'.
These metrics can be used to determine the performance limiting factor
when executing the trace, and how it will be affected by a code
transformation.
Initially, this will be used by the early if-conversion pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160796 91177308-0d34-0410-b5e6-96231b3b80d8
hopefully make it more visible. Adjust the web-docs to have a link to
this file rather than the list itself. I described code owners as also
being gatekeepers for their part of the code, which I think is true but
isn't in the code owner explanation on the web page.
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