some optimization opportunities (in the enclosing supper-expressions).
rule 1. (-0.0 - X ) * Y => -0.0 - (X * Y)
if expression "-0.0 - X" has only one reference.
rule 2. (0.0 - X ) * Y => -0.0 - (X * Y)
if expression "0.0 - X" has only one reference, and
the instruction is marked "noSignedZero".
2. Eliminate negation (The compiler was already able to handle these
opt if the 0.0s are replaced with -0.0.)
rule 3: (0.0 - X) * (0.0 - Y) => X * Y
rule 4: (0.0 - X) * C => X * -C
if the expr is flagged "noSignedZero".
3.
Rule 5: (X*Y) * X => (X*X) * Y
if X!=Y and the expression is flagged with "UnsafeAlgebra".
The purpose of this transformation is two-fold:
a) to form a power expression (of X).
b) potentially shorten the critical path: After transformation, the
latency of the instruction Y is amortized by the expression of X*X,
and therefore Y is in a "less critical" position compared to what it
was before the transformation.
4. Remove the InstCombine code about simplifiying "X * select".
The reasons are following:
a) The "select" is somewhat architecture-dependent, therefore the
higher level optimizers are not able to precisely predict if
the simplification really yields any performance improvement
or not.
b) The "select" operator is bit complicate, and tends to obscure
optimization opportunities. It is btter to keep it as low as
possible in expr tree, and let CodeGen to tackle the optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172551 91177308-0d34-0410-b5e6-96231b3b80d8
Test was failing for clang-native-arm-cortex-a9 build-bot configuration.
The reason for the failure was the test was using hardcoded names.
The attached patch fixes this failure by replacing the hard-coded variables
names with pattern-matched variable names.
Patch by Manish Verma, ARM
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172534 91177308-0d34-0410-b5e6-96231b3b80d8
---------------------------------------------------------------------------
C_A: reassociation is allowed
C_R: reciprocal of a constant C is appropriate, which means
- 1/C is exact, or
- reciprocal is allowed and 1/C is neither a special value nor a denormal.
-----------------------------------------------------------------------------
rule1: (X/C1) / C2 => X / (C2*C1) (if C_A)
=> X * (1/(C2*C1)) (if C_A && C_R)
rule 2: X*C1 / C2 => X * (C1/C2) if C_A
rule 3: (X/Y)/Z = > X/(Y*Z) (if C_A && at least one of Y and Z is symbolic value)
rule 4: Z/(X/Y) = > (Z*Y)/X (similar to rule3)
rule 5: C1/(X*C2) => (C1/C2) / X (if C_A)
rule 6: C1/(X/C2) => (C1*C2) / X (if C_A)
rule 7: C1/(C2/X) => (C1/C2) * X (if C_A)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172488 91177308-0d34-0410-b5e6-96231b3b80d8
Note that this bug is only exposed because LTO fails to use TTI.
Fixes self-LTO of clang. rdar://13007381.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172462 91177308-0d34-0410-b5e6-96231b3b80d8
The reason that this occurs is that tail calling objc_autorelease eventually
tail calls -[NSObject autorelease] which supports fast autorelease. This can
cause us to violate the semantic gaurantees of __autoreleasing variables that
assignment to an __autoreleasing variables always yields an object that is
placed into the innermost autorelease pool.
The fix included in this patch works by:
1. In the peephole optimization function OptimizeIndividualFunctions, always
remove tail call from objc_autorelease.
2. Whenever we convert to/from an objc_autorelease, set/unset the tail call
keyword as appropriate.
*NOTE* I also handled the case where objc_autorelease is converted in
OptimizeReturns to an autoreleaseRV which still violates the ARC semantics. I
will be removing that in a later patch and I wanted to make sure that the tree
is in a consistent state vis-a-vis ARC always.
Additionally some test cases are provided and all tests that have tail call marked
objc_autorelease keywords have been modified so that tail call has been removed.
*NOTE* One test fails due to a separate bug that I am going to commit soon. Thus
I marked the check line TMP: instead of CHECK: so make check does not fail.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172287 91177308-0d34-0410-b5e6-96231b3b80d8
the target if it supports the different CAST types. We didn't do this
on X86 because of the different register sizes and types, but on ARM
this makes sense.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172245 91177308-0d34-0410-b5e6-96231b3b80d8
We don't have a detailed analysis on which values are vectorized and which stay scalars in the vectorized loop so we use
another method. We look at reduction variables, loads and stores, which are the only ways to get information in and out
of loop iterations. If the data types are extended and truncated then the cost model will catch the cost of the vector
zext/sext/trunc operations.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172178 91177308-0d34-0410-b5e6-96231b3b80d8
Messages:
Converted test case trivial_codegen_tailcall.ll to use FileCheck.
Converted test return_constant.ll to use FileCheck instead of grep.
Converted test reorder_load.ll to use FileCheck instead of grep.
Converted test intervening-inst.ll to use FileCheck instead of grep.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172171 91177308-0d34-0410-b5e6-96231b3b80d8
The root cause is mistakenly taking for granted that
"dyn_cast<Instruction>(a-Value)"
return a non-NULL instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172145 91177308-0d34-0410-b5e6-96231b3b80d8
- this expression is explicitly marked no-signed-zero, or
- no-signed-zero of this expression can be derived from some context.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171922 91177308-0d34-0410-b5e6-96231b3b80d8
small loops. On small loops post-loop that handles scalars (and runs slower) can take more time to execute than the
rest of the loop. This patch disables widening of loops with a small static trip count.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171798 91177308-0d34-0410-b5e6-96231b3b80d8
o. X/C1 * C2 => X * (C2/C1) (if C2/C1 is neither special FP nor denormal)
o. X/C1 * C2 -> X/(C1/C2) (if C2/C1 is either specical FP or denormal, but C1/C2 is a normal Fp)
Let MDC denote multiplication or dividion with one & only one operand being a constant
o. (MDC ± C1) * C2 => (MDC * C2) ± (C1 * C2)
(so long as the constant-folding doesn't yield any denormal or special value)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171793 91177308-0d34-0410-b5e6-96231b3b80d8
turning a code like this:
if (foo)
free(foo)
into that:
free(foo)
Move a call to free from basic block FB into FB's predecessor, P,
when the path from P to FB is taken only if the argument of free is
not equal to NULL.
Some restrictions apply on P and FB to be sure that this code motion
is profitable. Namely:
1. FB must have only one predecessor P.
2. FB must contain only the call to free plus an unconditional
branch to S.
3. P's successors are FB and S.
Because of 1., we will not increase the code size when moving the call
to free from FB to P.
Because of 2., FB will be empty after the move.
Because of 2. and 3., P's branch instruction becomes useless, so as FB
(simplifycfg will do the job).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171762 91177308-0d34-0410-b5e6-96231b3b80d8
TargetTransformInfo rather than TargetLowering, removing one of the
primary instances of the layering violation of Transforms depending
directly on Target.
This is a really big deal because LSR used to be a "special" pass that
could only be tested fully using llc and by looking at the full output
of it. It also couldn't run with any other loop passes because it had to
be created by the backend. No longer is this true. LSR is now just
a normal pass and we should probably lift the creation of LSR out of
lib/CodeGen/Passes.cpp and into the PassManagerBuilder. =] I've not done
this, or updated all of the tests to use opt and a triple, because
I suspect someone more familiar with LSR would do a better job. This
change should be essentially without functional impact for normal
compilations, and only change behvaior of targetless compilations.
The conversion required changing all of the LSR code to refer to the TTI
interfaces, which fortunately are very similar to TargetLowering's
interfaces. However, it also allowed us to *always* expect to have some
implementation around. I've pushed that simplification through the pass,
and leveraged it to simplify code somewhat. It required some test
updates for one of two things: either we used to skip some checks
altogether but now we get the default "no" answer for them, or we used
to have no information about the target and now we do have some.
I've also started the process of removing AddrMode, as the TTI interface
doesn't use it any longer. In some cases this simplifies code, and in
others it adds some complexity, but I think it's not a bad tradeoff even
there. Subsequent patches will try to clean this up even further and use
other (more appropriate) abstractions.
Yet again, almost all of the formatting changes brought to you by
clang-format. =]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171735 91177308-0d34-0410-b5e6-96231b3b80d8
bogus comparison operands to default to eq/oeq. Fix that, fix a couple of
tests that accidentally passed and test for bogus comparison opeartors
explicitly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171733 91177308-0d34-0410-b5e6-96231b3b80d8
This could be simplified further, but Hal has a specific feature for
ignoring TTI, and so I preserved that.
Also, I needed to use it because a number of tests fail when switching
from a null TTI to the NoTTI nonce implementation. That seems suspicious
to me and so may be something that you need to look into Hal. I worked
it by preserving the old behavior for these tests with the flag that
ignores all target info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171722 91177308-0d34-0410-b5e6-96231b3b80d8
Since subtraction does not commute the loop vectorizer incorrectly vectorizes
reductions such as x = A[i] - x.
Disabling for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171537 91177308-0d34-0410-b5e6-96231b3b80d8
reachablity.
We conservatively approximate the reachability analysis by saying it is not
reachable if there is a single path starting from "From" and the path does not
reach "To".
rdar://12801584
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171512 91177308-0d34-0410-b5e6-96231b3b80d8
1. Add code to estimate register pressure.
2. Add code to select the unroll factor based on register pressure.
3. Add bits to TargetTransformInfo to provide the number of registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171469 91177308-0d34-0410-b5e6-96231b3b80d8
This is done to avoid odd test failures, like the one fixed in r171243.
While there, FileCheck'ize tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171344 91177308-0d34-0410-b5e6-96231b3b80d8
This is done to avoid odd test failures, like the one fixed in r171243.
My previous regex was not good enough to find these.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171343 91177308-0d34-0410-b5e6-96231b3b80d8
