Remove dead code. Improve llvm_unreachable text. Simplify some control flow.

llvm-svn: 150918

Fix typo.

llvm-svn: 149185

SCEVExpander fixes. Affects LSR and indvars.

LSR has gradually been improved to more aggressively reuse existing code, particularly existing phi cycles. This exposed problems with the SCEVExpander's

SCEVExpander fixes. Affects LSR and indvars.

LSR has gradually been improved to more aggressively reuse existing code, particularly existing phi cycles. This exposed problems with the SCEVExpander's sloppy treatment of its insertion point. I applied some rigor to the insertion point problem that will hopefully avoid an endless bug cycle in this area. Changes:

- Always used properlyDominates to check safe code hoisting.

- The insertion point provided to SCEV is now considered a lower bound. This is usually a block terminator or the use itself. Under no cirumstance may SCEVExpander insert below this point.

- LSR is reponsible for finding a "canonical" insertion point across expansion of different expressions.

- Robust logic to determine whether IV increments are in "expanded" form and/or can be safely hoisted above some insertion point.

Fixes PR11783: SCEVExpander assert.

llvm-svn: 148535

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Indvars: guard against exponential behavior in isHighCostExpansion.

This should always be done as a matter of principal. I don't have a
case that exposes the problem. I just noticed this recently wh

Indvars: guard against exponential behavior in isHighCostExpansion.

This should always be done as a matter of principal. I don't have a
case that exposes the problem. I just noticed this recently while
scanning the code and realized I meant to fix it long ago.

llvm-svn: 146438

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Add support for vectors of pointers.

llvm-svn: 145801

SCEV fix. In general, Add/Mul expressions should not inherit NSW/NUW.

This reverts r139450, fixes r139453, and adds much needed comments and a
unit test.

llvm-svn: 145367

Move code into anonymous namespaces.

llvm-svn: 145154

Rewrite LinearFunctionTestReplace to handle pointer-type IVs.

We've been hitting asserts in this code due to the many supported
combintions of modes (iv-rewrite/no-iv-rewrite) and IV types. This
sec

Rewrite LinearFunctionTestReplace to handle pointer-type IVs.

We've been hitting asserts in this code due to the many supported
combintions of modes (iv-rewrite/no-iv-rewrite) and IV types. This
second rewrite of the code attempts to deal with these cases systematically.

llvm-svn: 143546

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Add parentheses to disambiguate the precedence of these operations and
silence -Wparentheses.

llvm-svn: 143534

Broaden an assert to handle enable-iv-rewrite=true following r143183.

Narrowest possible fix for PR11279.

llvm-svn: 143522

LFTR should avoid a type mismatch with null pointer IVs.

Fixes rdar://10359193 Indvar LinearFunctionTestReplace assertion

llvm-svn: 143183

It is not safe to sink an alloca into a stacksave/stackrestore pair, so don't do that. <rdar://problem/10352360>

llvm-svn: 143093

Fix indvars randomness by removing iteration over a map.

I rewrote the algorithm a while back so it doesn't require map lookup,
but neglected to change the data structure. This was caught by
llvm-gc

Fix indvars randomness by removing iteration over a map.

I rewrote the algorithm a while back so it doesn't require map lookup,
but neglected to change the data structure. This was caught by
llvm-gcc self host, not because there's anything special about
llvm-gcc, but because it is the only test for nondeterminism we
currently have. Unit tests don't work well for everything; we should
always try to have a nondeterminism stress test running.

Fixes PR11133: llvm-gcc self host .o mismatch after enable-iv-rewrite=false

llvm-svn: 142036

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Move replaceCongruentIVs into SCEVExapander and bias toward "expanded"
IVs.

Indvars previously chose randomly between congruent IVs. Now it will
bias the decision toward IVs that SCEVExpander likes

Move replaceCongruentIVs into SCEVExapander and bias toward "expanded"
IVs.

Indvars previously chose randomly between congruent IVs. Now it will
bias the decision toward IVs that SCEVExpander likes to create. This
was not done to fix any problem, it's just a welcome side effect of
factoring code.

llvm-svn: 141633

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indvars should hoist [sz]ext because licm is not rerun.

llvm-svn: 140670

Reapply r139759. Disable IV rewriting by default. See PR10916.

llvm-svn: 139842

[indvars] Revert r139579 until 401.bzip -arch i386 miscompilation is fixed. PR10920.

llvm-svn: 139583

Disable IV rewriting by default. See PR10916.

llvm-svn: 139579

[indvars] Fix bugs in floating point IV range checks noticed by inspection.

llvm-svn: 139574

Rename -disable-iv-rewrite to -enable-iv-rewrite=false in preparation for default change.

llvm-svn: 139517

[disable-iv-rewrite] Allow WidenIV to handle NSW/NUW operations
better.

Don't immediately give up when an add operation can't be trivially
sign/zero-extended within a loop. If it has NSW/NUW flags,

[disable-iv-rewrite] Allow WidenIV to handle NSW/NUW operations
better.

Don't immediately give up when an add operation can't be trivially
sign/zero-extended within a loop. If it has NSW/NUW flags, generate a
new expression with sign extended (non-recurrent) operand. As before,
if SCEV says that all sign extends are loop invariant, then we can
widen the operation.

llvm-svn: 139453

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Comment formatting.

llvm-svn: 139375

Add -verify-indvars for imperfect SCEV trip count verification after indvars.

llvm-svn: 139169

Don't sink landingpad instructions during ind-var simplification.

llvm-svn: 138651

Use getFirstInsertionPt instead of getFirstNonPHI so that it skips to the proper
insertion place.

llvm-svn: 138473