Summary:
The correctness fix here is that when we CSE a load with another load,
we need to combine the metadata on the two loads. This matches the
behavior of other passes, like instcombine and GVN.
There's also a minor optimization improvement here: for load PRE, the
aliasing metadata on the inserted load should be the same as the
metadata on the original load. Not sure why the old code was throwing
it away.
Issue found by inspection.
Differential Revision: http://reviews.llvm.org/D21460
llvm-svn: 277977
Fixes PR28764. Right now there is no way to test this, but (as
mentioned on the PR) with Michael Zolotukhin's yet to be checked in
LoopSimplify verfier, 8 of the llvm-lit tests for IRCE crash.
llvm-svn: 277891
Summary:
This is another refactoring to break up the one function into three logical components functions.
Another non-functional change before we start added in features.
Reviewers: nadav, mehdi_amini, majnemer
Subscribers: twoh, freik, llvm-commits
Differential Revision: https://reviews.llvm.org/D23102
llvm-svn: 277855
The patch splits a complex && if condition into easier to read and understand
logic. That wrong early exit condition was letting some instructions with not
all operands available pass through when HoistingGeps was true.
Differential Revision: https://reviews.llvm.org/D23174
llvm-svn: 277785
Limit the number of times the while(1) loop is executed. With this restriction
the number of hoisted instructions does not change in a significant way on the
test-suite.
Differential Revision: https://reviews.llvm.org/D23028
llvm-svn: 277651
With this patch we compute the DFS numbers of instructions only once and update
them during the code generation when an instruction gets hoisted.
Differential Revision: https://reviews.llvm.org/D23021
llvm-svn: 277650
With this patch we compute the MemorySSA once and update it in the code generator.
Differential Revision: https://reviews.llvm.org/D22966
llvm-svn: 277649
Summary:
This is the first refactoring before adding new functionality.
Add a class wrapper for the functions and container for
state associated with the transformation.
No functional change
Reviewers: majnemer, nadav, mehdi_amini
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D23065
llvm-svn: 277565
LoopUnroll is a loop pass, so the analysis of OptimizationRemarkEmitter
is added to the common function analysis passes that loop passes
depend on.
The BFI and indirectly BPI used in this pass is computed lazily so no
overhead should be observed unless -pass-remarks-with-hotness is used.
This is how the patch affects the O3 pipeline:
Dominator Tree Construction
Natural Loop Information
Canonicalize natural loops
Loop-Closed SSA Form Pass
Basic Alias Analysis (stateless AA impl)
Function Alias Analysis Results
Scalar Evolution Analysis
+ Lazy Branch Probability Analysis
+ Lazy Block Frequency Analysis
+ Optimization Remark Emitter
Loop Pass Manager
Rotate Loops
Loop Invariant Code Motion
Unswitch loops
Simplify the CFG
Dominator Tree Construction
Basic Alias Analysis (stateless AA impl)
Function Alias Analysis Results
Combine redundant instructions
Natural Loop Information
Canonicalize natural loops
Loop-Closed SSA Form Pass
Scalar Evolution Analysis
+ Lazy Branch Probability Analysis
+ Lazy Block Frequency Analysis
+ Optimization Remark Emitter
Loop Pass Manager
Induction Variable Simplification
Recognize loop idioms
Delete dead loops
Unroll loops
...
llvm-svn: 277203
Some instructions may have their uses replaced with a symbolic constant.
However, the instruction may still have side effects which percludes it
from being removed from the function. EarlyCSE treated such an
instruction as if it were removed, resulting in PR28763.
llvm-svn: 277114
A ConstantVector can have ConstantExpr operands and vice versa.
However, the folder had no ability to fold ConstantVectors which, in
some cases, was an optimization barrier.
Instead, rephrase the folder in terms of Constants instead of
ConstantExprs and teach callers how to deal with failure.
llvm-svn: 277099
Summary: The MadeChange flag should be ORed to keep the previous result.
Reviewers: mcrosier
Subscribers: mcrosier, llvm-commits
Differential Revision: https://reviews.llvm.org/D22873
llvm-svn: 276894
When loading or storing in a field of a struct like "a.b.c", GVN is able to
detect the equivalent expressions, and GVN-hoist would fail in the code
generation. This is because the GEPs are not hoisted as scalar operations to
avoid moving the GEPs too far from their ld/st instruction when the ld/st is not
movable. So we end up having to generate code for the GEP of a ld/st when we
move the ld/st. In the case of a GEP referring to another GEP as in "a.b.c" we
need to code generate all the GEPs necessary to make all the operands available
at the new location for the ld/st. With this patch we recursively walk through
the GEP operands checking whether all operands are available, and in the case of
a GEP operand, it recursively makes all its operands available. Code generation
happens from the inner GEPs out until reaching the GEP that appears as an
operand of the ld/st.
Differential Revision: https://reviews.llvm.org/D22599
llvm-svn: 276841
The patch replaces a function that walks the IR with a call to firstInBB() that
uses the DFS numbering. NFC.
Differential Revision: https://reviews.llvm.org/D22809
llvm-svn: 276840
Instead of DFS numbering basic blocks we now DFS number instructions that avoids
the costly operation of which instruction comes first in a basic block.
Patch mostly written by Daniel Berlin.
Differential Revision: https://reviews.llvm.org/D22777
llvm-svn: 276714
This patch adds an option to specify the maximum depth in a BB at which to
consider hoisting instructions. Hoisting instructions from a deeper level is
not profitable as it increases register pressure and compilation time.
Differential Revision: https://reviews.llvm.org/D22772
llvm-svn: 276713
If we two loads of two different alignments, we must use the minimum of
the two alignments when hoisting. Same deal for stores.
For allocas, use the maximum of the two allocas.
llvm-svn: 276601
Allowed loop vectorization with secondary FP IVs. Like this:
float *A;
float x = init;
for (int i=0; i < N; ++i) {
A[i] = x;
x -= fp_inc;
}
The auto-vectorization is possible when the induction binary operator is "fast" or the function has "unsafe" attribute.
Differential Revision: https://reviews.llvm.org/D21330
llvm-svn: 276554
Recommiting r275571 after fixing crash reported in PR28270.
Now we erase elements of IOL in deleteDeadInstruction().
Original Summary:
This change use the overlap interval map built from partial overwrite tracking to perform shortening MemIntrinsics.
Add test cases which was missing opportunities before.
llvm-svn: 276452
Just because we can constant fold the result of an instruction does not
imply that we can delete the instruction. It may have side effects.
This fixes PR28655.
llvm-svn: 276389
If `-irce-skip-profitability-checks` is passed in, IRCE will kick in in
all cases where it is legal for it to kick in. This flag is intended to
help diagnose and analyse performance issues.
llvm-svn: 276372
Do not clone stored values unless they are GEPs that are special cased to avoid
hoisting them without hoisting their associated ld/st.
Differential revision: https://reviews.llvm.org/D22652
llvm-svn: 276358
Sean Silva