The motivation for this patch starts with PR20134:
https://llvm.org/bugs/show_bug.cgi?id=20134
void foo(int *a, int i) {
a[i] = a[i+1] + a[i+2];
}
It seems better to produce this (14 bytes):
movslq %esi, %rsi
movl 0x4(%rdi,%rsi,4), %eax
addl 0x8(%rdi,%rsi,4), %eax
movl %eax, (%rdi,%rsi,4)
Rather than this (22 bytes):
leal 0x1(%rsi), %eax
cltq
leal 0x2(%rsi), %ecx
movslq %ecx, %rcx
movl (%rdi,%rcx,4), %ecx
addl (%rdi,%rax,4), %ecx
movslq %esi, %rax
movl %ecx, (%rdi,%rax,4)
The most basic problem (the first test case in the patch combines constants) should also be fixed in InstCombine,
but it gets more complicated after that because we need to consider architecture and micro-architecture. For
example, AArch64 may not see any benefit from the more general transform because the ISA solves the sexting in
hardware. Some x86 chips may not want to replace 2 ADD insts with 1 LEA, and there's an attribute for that:
FeatureSlowLEA. But I suspect that doesn't go far enough or maybe it's not getting used when it should; I'm
also not sure if FeatureSlowLEA should also mean "slow complex addressing mode".
I see no perf differences on test-suite with this change running on AMD Jaguar, but I see small code size
improvements when building clang and the LLVM tools with the patched compiler.
A more general solution to the sext(add nsw(x, C)) problem that works for multiple targets is available
in CodeGenPrepare, but it may take quite a bit more work to get that to fire on all of the test cases that
this patch takes care of.
Differential Revision: http://reviews.llvm.org/D13757
llvm-svn: 250560
Crashing is bad, m'kay? Fixing a 4 year old bug of my own creation.
Adding the testcase now which I should have added then which would have
long since caught this.
The problem is that printMessage() will display the diagnostic but not
set HadError to true, resulting in the assembler continuing on its way
and trying to create relocations for things that may not allow them or
otherwise get itself into trouble. Using the Error() helper function
here rather than calling printMessage() directly resolves this.
rdar://23133240
llvm-svn: 250557
Summary:
We now use the block for the catchpad itself, rather than its normal
successor, as the funclet entry.
Putting the normal successor in the map leads downstream funclet
membership computations to erroneous results.
Reviewers: majnemer, rnk
Subscribers: rnk, llvm-commits
Differential Revision: http://reviews.llvm.org/D13798
llvm-svn: 250552
The number of samples collected at the head of a function only make
sense for top-level functions (i.e., those actually called as opposed to
being inlined inside another).
Head samples essentially count the time spent inside the function's
prologue. This clearly doesn't make sense for inlined functions, so we
were always emitting 0 in those.
llvm-svn: 250539
Summary: The syntax has changed a bit recently.
Reviewers: binji
Subscribers: llvm-commits, jfb, sunfish, dschuff
Differential Revision: http://reviews.llvm.org/D13821
llvm-svn: 250535
Summary:
When a cleanup's cleanupendpad or cleanupret targets a catchendpad, stop
trying to propagate the cleanup's parent's color to the catchendpad, since
what's needed is the cleanup's grandparent's color and the catchendpad
will get that color from the catchpad linkage already. We already had
this exclusion for invokes, but were missing it for
cleanupendpad/cleanupret.
Also add a missing line that tags cleanupendpads' states in the
EHPadStateMap, without with lowering invokes that target cleanupendpads
which unwind to other handlers (and so don't have the -1 state) will fail.
This fixes the reduced IR repro in PR25163.
Reviewers: majnemer, andrew.w.kaylor, rnk
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13797
llvm-svn: 250534
Ideally, we would like SimplifyCFG to be able to form select instructions even when the operands
are expensive (as defined by the TTI cost model) because that may expose further optimizations.
However, we would then like a later pass like CodeGenPrepare to undo that transformation if the
target would likely benefit from not speculatively executing an expensive op (this patch).
Once we have this safety mechanism in place, we can adjust SimplifyCFG to restore its
select-formation behavior that changed with r248439.
Differential Revision: http://reviews.llvm.org/D13297
llvm-svn: 250527
Summary: Make the relooper an analysis pass, to convert CFG to AST.
Reviewers: sunfish
Subscribers: jfb, dschuff
Differential Revision: http://reviews.llvm.org/D12744
llvm-svn: 250524
Summary: This patch replaces usage of deprecated SHGetFolderPathW with SHGetKnownFolderPath. The usage of SHGetKnownFolderPath is wrapped to allow queries for other "known" folders in the near future.
Reviewers: aaron.ballman, gbedwell
Subscribers: chapuni, llvm-commits
Differential Revision: http://reviews.llvm.org/D13753
llvm-svn: 250501
This patch adds the underlying infrastructure for an AVR backend to be included into LLVM. It is the first of a series of patches aimed at moving the out-of-tree AVR backend into the tree.
It consists of adding a new`Triple` target 'avr'.
llvm-svn: 250492
The `"statepoint-id"` and `"statepoint-num-patch-bytes"` attributes are
used solely to determine properties of the `gc.statepoint` being
created. Once the `gc.statepoint` is in place, these should be removed.
llvm-svn: 250491
Summary:
This is a step towards using operand bundles to carry deopt state till
RewriteStatepointsForGC. The change adds a flag to
RewriteStatepointsForGC that teaches it to pick up deopt state from a
`"deopt"` operand bundle attached to the `call` or `invoke` it is
wrapping.
The command line flag added, `-rs4gc-use-deopt-bundles`, will only exist
for a short while. Once we are able to pipe deopt bundle state through
the full optimization pipeline without problems, we will "constant fold"
`-rs4gc-use-deopt-bundles` to `true`.
Reviewers: swaroop.sridhar, reames
Subscribers: llvm-commits, sanjoy
Differential Revision: http://reviews.llvm.org/D13372
llvm-svn: 250489
Summary:
`cloneArithmeticIVUser` currently trips over expression like `add %iv,
-1` when `%iv` is being zero extended -- it tries to construct the
widened use as `add %iv.zext, zext(-1)` and (correctly) fails to prove
equivalence to `zext(add %iv, -1)` (here the SCEV for `%iv` is
`{1,+,1}`).
This change teaches `IndVars` to try sign extending the non-IV operand
if that makes the newly constructed IV use equivalent to the widened
narrow IV use.
Reviewers: atrick, hfinkel, reames
Subscribers: sanjoy, llvm-commits
Differential Revision: http://reviews.llvm.org/D13717
llvm-svn: 250483
Summary:
This NFC splitting is intended to make a later diff easier to follow.
It just tail duplicates `cloneIVUser` into `cloneArithmeticIVUser` and
`cloneBitwiseIVUser`.
Reviewers: atrick, hfinkel, reames
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D13716
llvm-svn: 250481
Summary:
Follow the same syntax as for the spec repo. Both have evolved slightly
independently and need to converge again.
This, along with wasmate changes, allows me to do the following:
echo "int add(int a, int b) { return a + b; }" > add.c
./out/bin/clang -O2 -S --target=wasm32-unknown-unknown add.c -o add.wack
./experimental/prototype-wasmate/wasmate.py add.wack > add.wast
./sexpr-wasm-prototype/out/sexpr-wasm add.wast -o add.wasm
./sexpr-wasm-prototype/third_party/v8-native-prototype/v8/v8/out/Release/d8 -e "print(WASM.instantiateModule(readbuffer('add.wasm'), {print:print}).add(42, 1337));"
As you'd expect, the d8 shell prints out the right value.
Reviewers: sunfish
Subscribers: jfb, llvm-commits, dschuff
Differential Revision: http://reviews.llvm.org/D13712
llvm-svn: 250480
Android libc provides a fixed TLS slot for the unsafe stack pointer,
and this change implements direct access to that slot on AArch64 via
__builtin_thread_pointer() + offset.
This change also moves more code into TargetLowering and its
target-specific subclasses to get rid of target-specific codegen
in SafeStackPass.
This change does not touch the ARM backend because ARM lowers
builting_thread_pointer as aeabi_read_tp, which is not available
on Android.
llvm-svn: 250456
Summary:
Sometimes you want to install a custom compiler and use it like the system compiler without overriding the system compiler. This patch lets you create xctoolchains that the darwin command line tools can use.
To use this patch set LLVM_CREATE_XCODE_TOOLCHAIN=On in your CMake invocation and build the `install-code-toolchain` target.
After installation you can set the envar EXTERNAL_TOOLCHAINS_DIR to your installed Toolchains directory, and the TOOLCHAINS envar to the toolchain identifier (ex org.llvm.3.8.0svn). This will then cause /usr/bin/clang to call your newly installed clang.
Reviewers: Bigcheese, bogner
Subscribers: tobiasfar, llvm-commits
Differential Revision: http://reviews.llvm.org/D13605
llvm-svn: 250450
D4796 taught LLVM to fold some atomic integer operations into a single
instruction. The pattern was unaware that the instructions clobbered
flags. I fixed some of this issue in D13680 but had missed INC/DEC.
This patch adds the missing EFLAGS definition.
llvm-svn: 250438
The DEBUG() macro has required that a DEBUG_TYPE be set since r206822.
Update the programmers manual to reflect that, and also update the
wording to point out that DEBUG_TYPE should be defined after #includes.
llvm-svn: 250436
Turns out this approach is buggy. In discussion about follow on work, Sanjoy pointed out that we could be subject to circular logic problems.
Consider:
if (i u< L) leave()
if ((i + 1) u< L) leave()
print(a[i] + a[i+1])
If we know that L is less than UINT_MAX, we could possible prove (in a control dependent way) that i + 1 does not overflow. This gives us:
if (i u< L) leave()
if ((i +nuw 1) u< L) leave()
print(a[i] + a[i+1])
If we now do the transform this patch proposed, we end up with:
if ((i +nuw 1) u< L) leave_appropriately()
print(a[i] + a[i+1])
That would be a miscompile when i==-1. The problem here is that the control dependent nuw bits got used to prove something about the first condition. That's obviously invalid.
This won't happen today, but since I plan to enhance LVI/CVP with exactly that transform at some point in the not too distant future...
llvm-svn: 250430
