bug fixes, and with improved heuristics for analyzing foreign-loop
addrecs.
This change also flattens IVUsers, eliminating the stride-oriented
groupings, which makes it easier to work with.
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This new version is much more aggressive about doing "full" reduction in
cases where it reduces register pressure, and also more aggressive about
rewriting induction variables to count down (or up) to zero when doing so
reduces register pressure.
It currently uses fairly simplistic algorithms for finding reuse
opportunities, but it introduces a new framework allows it to combine
multiple strategies at once to form hybrid solutions, instead of doing
all full-reduction or all base+index.
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input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.
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- I'd appreciate it if someone else eyeballs my changes to make sure I captured
the intent of the test.
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sinking code, since they are special. If the loop preheader happens
to be the entry block of a function, don't sink static allocas
out of it. This fixes PR4775.
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TargetData is not present. It still uses TargetData when available.
This generalization also fixed some limitations in the TargetData
case; the attached testcase covers this.
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Getelementptrs that are defined to wrap are virtually useless to
optimization, and getelementptrs that are undefined on any kind
of overflow are too restrictive -- it's difficult to ensure that
all intermediate addresses are within bounds. I'm going to take
a different approach.
Remove a few optimizations that depended on this flag.
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the operands have pointer type, so that the resulting type matches
the original SCEV type, and so that unnecessary ptrtoints are
avoided in common cases.
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check for avoiding re-analyzing a widening cast needed to happen
earlier, as getSCEV itself may result in a isLoopGuardedByCond query.
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of loops. Add several new functions to for working with ScalarEvolution's
add-hoc value-range analysis functionality.
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an individual exhaustive evaluation reflects only the exit value
implied by an individual exit, which may differ from the actual
exit value of the loop if there are other exits. This fixes PR4477.
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inserted to replace that value must dominate all of of the basic
blocks associated with the uses of the value in the PHI, not just
one of them.
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computations in loops with multiple exits.
Adjust the testcase for PR4436 so that the relevant portion isn't
optimized away.
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terminator, instead of after the last phi. This fixes a bug
exposed by ScalarEvolution analyzing more kinds of loops.
This fixes PR4436.
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SCEVUnknowns with identical Instructions to be equal. This allows
it to analze cases such as the attached testcase, where the front-end
has cloned the loop controlling expression. Along with r73805, this
lets IndVarSimplify eliminate all the sign-extend casts in the
loop in the attached testcase.
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casted induction variables in cases where the cast
isn't foldable. It ended up being a pessimization in
many cases. This could be fixed, but it would require
a bunch of complicated code in IVUsers' clients. The
advantages of this approach aren't visible enough to
justify it at this time.
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obscuring what would otherwise be a low-bits mask. Use ComputeMaskedBits
to compute what ShrinkDemandedConstant knew about to reconstruct a
low-bits mask value.
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they contain multiplications of constants with add operations.
This helps simplify several kinds of things; in particular it
helps simplify expressions like ((-1 * (%a + %b)) + %a) to %b,
as expressions like this often come up in loop trip count
computations.
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induction variable when the addrec to be expanded does not require
a wider type. This eliminates the need for IndVarSimplify to
micro-manage SCEV expansions, because SCEVExpander now
automatically expands them in the form that IndVarSimplify considers
to be canonical. (LSR still micro-manages its SCEV expansions,
because it's optimizing for the target, rather than for
other optimizations.)
Also, this uses the new getAnyExtendExpr, which has more clever
expression simplification logic than the IndVarSimplify code it
replaces, and this cleans up some ugly expansions in code such as
the included masked-iv.ll testcase.
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integer and floating-point opcodes, introducing
FAdd, FSub, and FMul.
For now, the AsmParser, BitcodeReader, and IRBuilder all preserve
backwards compatability, and the Core LLVM APIs preserve backwards
compatibility for IR producers. Most front-ends won't need to change
immediately.
This implements the first step of the plan outlined here:
http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt
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possible. For example, it now emits
%p.2.ip.1 = getelementptr [3 x [3 x double]]* %p, i64 2, i64 %tmp, i64 1
instead of the equivalent but less obvious
%p.2.ip.1 = getelementptr [3 x [3 x double]]* %p, i64 0, i64 %tmp, i64 19
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division operation, don't attempt to use the operation's value as
the base of a getelementptr. This fixes PR4271.
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leave the original comparison in place if it has other uses, since the
other uses won't be dominated by the new comparison instruction.
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sending SCEVUnknowns to expandAddToGEP. This avoids the need for
expandAddToGEP to bend the rules and peek into SCEVUnknown
expressions.
Factor out the code for testing whether a SCEV can be factored by
a constant for use in a GEP index. This allows it to handle
SCEVAddRecExprs, by recursing.
As a result, SCEVExpander can now put more things in GEP indices,
so it emits fewer explicit mul instructions.
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Fix by clearing the rewriter cache before deleting the trivially dead
instructions.
Also make InsertedExpressions use an AssertingVH to catch these
bugs easier.
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assuming that the use of the value is in a block dominated by the
"normal" destination. LangRef.html and other documentation sources
don't explicitly guarantee this, but it seems to be assumed in
other places in LLVM at least.
This fixes an assertion failure on the included testcase, which
is derived from the Ada testsuite.
FixUsesBeforeDefs is a temporary measure which I'm looking to
replace with a more capable solution.
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use in expanding SCEVAddExprs with GEPs. The operands of a
SCEVMulExpr need to be multiplied together, not added.
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instructions. It attempts to create high-level multi-operand GEPs,
though in cases where this isn't possible it falls back to casting
the pointer to i8* and emitting a GEP with that. Using GEP instructions
instead of ptrtoint+arithmetic+inttoptr helps pointer analyses that
don't use ScalarEvolution, such as BasicAliasAnalysis.
Also, make the AddrModeMatcher more aggressive in handling GEPs.
Previously it assumed that operand 0 of a GEP would require a register
in almost all cases. It now does extra checking and can do more
matching if operand 0 of the GEP is foldable. This fixes a problem
that was exposed by SCEVExpander using GEPs.
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