[SCEV] Fix ScalarEvolution tests under NPM
Many tests use opt's -analyze feature, which does not translate well to
NPM and has better alternatives. The alternative here is to explicitly
add a pass that calls ScalarEvolution::print().
The legacy pass manager RUNs aren't changing, but they are now pinned to
the legacy pass manager. For each legacy pass manager RUN, I added a
corresponding NPM RUN using the 'print<scalar-evolution>' pass. For
compatibility with update_analyze_test_checks.py and existing test
CHECKs, 'print<scalar-evolution>' now prints what -analyze prints per
function.
This was generated by the following Python script and failures were
manually fixed up:
import sys
for i in sys.argv:
with open(i, 'r') as f:
s = f.read()
with open(i, 'w') as f:
for l in s.splitlines():
if "RUN:" in l and ' -analyze ' in l and '\\' not in l:
f.write(l.replace(' -analyze ', ' -analyze -enable-new-pm=0 '))
f.write('\n')
f.write(l.replace(' -analyze ', ' -disable-output ').replace(' -scalar-evolution ', ' "-passes=print<scalar-evolution>" ').replace(" | ", " 2>&1 | "))
f.write('\n')
else:
f.write(l)
There are a couple failures still in ScalarEvolution under NPM, but
those are due to other unrelated naming conflicts.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D83798
2020-07-17 02:09:47 +08:00
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; RUN: opt -disable-output "-passes=print<scalar-evolution>" -scalar-evolution-max-add-rec-size=3 < %s 2>&1 | FileCheck %s
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[SCEV] Limit max size of AddRecExpr during evolving
When SCEV calculates product of two SCEVAddRecs from the same loop, it
tries to combine them into one big AddRecExpr. If the sizes of the initial
SCEVs were `S1` and `S2`, the size of their product is `S1 + S2 - 1`, and every
operand of the resulting SCEV is combined from operands of initial SCEV and
has much higher complexity than they have.
As result, if we try to calculate something like:
%x1 = {a,+,b}
%x2 = mul i32 %x1, %x1
%x3 = mul i32 %x2, %x1
%x4 = mul i32 %x3, %x2
...
The size of such SCEVs grows as `2^N`, and the arguments
become more and more complex as we go forth. This leads
to long compilation and huge memory consumption.
This patch sets a limit after which we don't try to combine two
`SCEVAddRecExpr`s into one. By default, max allowed size of the
resulting AddRecExpr is set to 16.
Differential Revision: https://reviews.llvm.org/D35664
llvm-svn: 308847
2017-07-23 23:40:19 +08:00
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; Show that we are able to avoid creation of huge SCEVs by capping the max
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; AddRec size.
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define i32 @test_01(i32 %a, i32 %b) {
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; CHECK-LABEL: Classifying expressions for: @test_01
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; CHECK-NEXT: %iv = phi i32 [ %a, %entry ], [ %iv.next, %loop ]
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; CHECK-NEXT: --> {%a,+,%b}<%loop> U: full-set S: full-set
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; CHECK-NEXT: %iv.next = add i32 %iv, %b
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; CHECK-NEXT: --> {(%a + %b),+,%b}<%loop> U: full-set S: full-set
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; CHECK-NEXT: %x1 = mul i32 %iv, %iv.next
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; CHECK-NEXT: --> {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> U: full-set S: full-set
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; CHECK-NEXT: %x2 = mul i32 %x1, %x1
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; CHECK-NEXT: --> ({((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop>) U: full-set S: full-set
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; CHECK-NEXT: %x3 = mul i32 %x2, %x1
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; CHECK-NEXT: --> ({((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop> * {((%a + %b) * %a),+,(((2 * %a) + (2 * %b)) * %b),+,(2 * %b * %b)}<%loop>) U: full-set S: full-set
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %a, %entry ], [ %iv.next, %loop ]
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%iv.next = add i32 %iv, %b
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%cond = icmp slt i32 %iv.next, 1000
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br i1 %cond, label %loop, label %exit
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exit:
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%x1 = mul i32 %iv, %iv.next
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%x2 = mul i32 %x1, %x1
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%x3 = mul i32 %x2, %x1
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ret i32 %x3
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}
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