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Differential D62664

[DAGCombine] (A+C1)-C2 -> A+(C1-C2) constant-fold
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Authored by lebedev.ri on May 30 2019, 7:14 AM.

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Reviewers
RKSimon
craig.topper
spatel
t.p.northover
Commits
rG0a3dbbcdfb54: [DAGCombine] (A+C1)-C2 -> A+(C1-C2) constant-fold
rL362133: [DAGCombine] (A+C1)-C2 -> A+(C1-C2) constant-fold
Summary

Direct sibling of D62662, the root cause of the endless combine loop in D62257

https://rise4fun.com/Alive/d3W

Diff Detail

Repository
rL LLVM

Event Timeline

lebedev.ri created this revision.May 30 2019, 7:14 AM
Herald added a subscriber: javed.absar. · View Herald TranscriptMay 30 2019, 7:14 AM
lebedev.ri added a parent revision: D62663: [DAGCombine] Use FoldConstantArithmetic() to perform C2-(A+C1) -> (C2-C1)-A fold.May 30 2019, 7:15 AM
lebedev.ri added a child revision: D62257: [DAGCombiner][X86][AArch64] (x - C) + y -> (x + y) - C fold.
lebedev.ri updated this revision to Diff 202223.May 30 2019, 9:12 AM

Better test coverage.

lebedev.ri added a child revision: D62689: [DAGCombine] (A-C1)-C2 -> A-(C1+C2) constant-fold.May 30 2019, 9:36 AM
lebedev.ri removed a child revision: D62257: [DAGCombiner][X86][AArch64] (x - C) + y -> (x + y) - C fold.
lebedev.ri updated this revision to Diff 202230.May 30 2019, 9:55 AM

And actually fix the test coverage (:
Sorry for the noise.

t.p.northover accepted this revision.May 30 2019, 9:56 AM
t.p.northover added a subscriber: t.p.northover.

Looks reasonable.

This revision is now accepted and ready to land.May 30 2019, 9:56 AM
Closed by commit rL362133: [DAGCombine] (A+C1)-C2 -> A+(C1-C2) constant-fold (authored by lebedevri). · Explain WhyMay 30 2019, 12:25 PM
This revision was automatically updated to reflect the committed changes.

Revision Contents
Changeset List

PathSize
llvm/
trunk/
lib/
CodeGen/
SelectionDAG/
10 lines
test/
CodeGen/
AArch64/
13 lines
X86/
16 lines

Diff 202272

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llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

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llvm/trunk/test/CodeGen/AArch64/addsub-constant-folding.ll

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llvm/trunk/test/CodeGen/X86/addsub-constant-folding.ll

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