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[SCEV] When printing via -analysis, dump loop disposition

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There are currently some bugs in tree around SCEV caching an incorrect
loop disposition.  Printing out loop dispositions will let us write
whitebox tests as those are fixed.

The dispositions are printed as a list in "inside out" order,
i.e. innermost loop first.

llvm-svn: 268177
This commit is contained in:
Sanjoy Das 2016-05-01 04:51:05 +00:00
parent 8a367d404f
commit f2f00fb11a
2 changed files with 98 additions and 0 deletions
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25
llvm/lib/Analysis/ScalarEvolution.cpp
View File

@ -9565,6 +9565,17 @@ static void PrintLoopInfo(raw_ostream &OS, ScalarEvolution *SE,
OS << "\n";
}
static StringRef loopDispositionToStr(ScalarEvolution::LoopDisposition LD) {
switch (LD) {
case ScalarEvolution::LoopVariant:
return "Variant";
case ScalarEvolution::LoopInvariant:
return "Invariant";
case ScalarEvolution::LoopComputable:
return "Computable";
}
}
void ScalarEvolution::print(raw_ostream &OS) const {
// ScalarEvolution's implementation of the print method is to print
// out SCEV values of all instructions that are interesting. Doing
@ -9612,6 +9623,20 @@ void ScalarEvolution::print(raw_ostream &OS) const {
} else {
OS << *ExitValue;
}
bool First = true;
for (auto *Iter = L; Iter; Iter = Iter->getParentLoop()) {
if (First) {
OS << "\t\t" "LoopDispositions: [ ";
First = false;
} else {
OS << ", ";
}
OS << loopDispositionToStr(SE.getLoopDisposition(SV, Iter));
}
OS << " ]";
}
OS << "\n";

73
llvm/test/Analysis/ScalarEvolution/scev-dispositions.ll Normal file
View File

@ -0,0 +1,73 @@
; RUN: opt -analyze -scalar-evolution < %s | FileCheck %s
define void @single_loop(i32* %buf, i32 %start) {
; CHECK-LABEL: Classifying expressions for: @single_loop
entry:
%val = add i32 %start, 400
br label %loop
loop:
%counter = phi i32 [ 0, %entry ], [ %counter.inc, %loop ]
%idx = phi i32 [ %start, %entry ], [ %idx.inc, %loop ]
; CHECK: %counter = phi i32 [ 0, %entry ], [ %counter.inc, %loop ]
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable ]
; CHECK: %idx = phi i32 [ %start, %entry ], [ %idx.inc, %loop ]
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable ]
; CHECK: %val2 = add i32 %start, 400
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Invariant ]
; CHECK: %idx.inc = add nsw i32 %idx, 1
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable ]
; CHECK: %val3 = load volatile i32, i32* %buf
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Variant ]
%val2 = add i32 %start, 400
%idx.inc = add nsw i32 %idx, 1
%idx.inc.sext = sext i32 %idx.inc to i64
%condition = icmp eq i32 %counter, 1
%counter.inc = add i32 %counter, 1
%val3 = load volatile i32, i32* %buf
br i1 %condition, label %exit, label %loop
exit:
ret void
}
define void @nested_loop(double* %p, i64 %m) {
; CHECK-LABEL: Classifying expressions for: @nested_loop
; CHECK: %j = phi i64 [ 0, %entry ], [ %j.next, %outer.latch ]
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable ]
; CHECK: %i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable, Variant ]
; CHECK: %j.add = add i64 %j, 100
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Invariant, Computable ]
; CHECK: %i.next = add i64 %i, 1
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable, Variant ]
; CHECK: %j.next = add i64 %j, 91
; CHECK-NEXT: --> {{.*}} LoopDispositions: [ Computable ]
entry:
%k = icmp sgt i64 %m, 0
br i1 %k, label %outer.loop, label %return
outer.loop:
%j = phi i64 [ 0, %entry ], [ %j.next, %outer.latch ]
br label %bb
bb:
%i = phi i64 [ 0, %outer.loop ], [ %i.next, %bb ]
%j.add = add i64 %j, 100
%i.next = add i64 %i, 1
%exitcond = icmp eq i64 %i.next, 91
br i1 %exitcond, label %outer.latch, label %bb
outer.latch:
%j.next = add i64 %j, 91
%h = icmp eq i64 %j.next, %m
br i1 %h, label %return, label %outer.loop
return:
ret void
}