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https://github.com/c64scene-ar/llvm-6502.git
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de87c9165a
If x is known to have the range [a, b), in a loop predicated by (icmp ne x, a) its range can be sharpened to [a + 1, b). Get ScalarEvolution and hence IndVars to exploit this fact. This change triggers an optimization to widen-loop-comp.ll, so it had to be edited to get it to pass. This change was originally landed in r219834 but had a bug and broke ASan. It was reverted in r219878, and is now being re-landed after fixing the original bug. phabricator: http://reviews.llvm.org/D5639 reviewed by: atrick git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221839 91177308-0d34-0410-b5e6-96231b3b80d8
114 lines
2.4 KiB
LLVM
114 lines
2.4 KiB
LLVM
;; RUN: opt -S < %s -indvars | FileCheck %s
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;; Check if llvm can narrow !range metadata based on loop entry
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;; predicates.
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declare void @abort()
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define i1 @bounded_below_slt(i32* nocapture readonly %buffer) {
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; CHECK-LABEL: bounded_below_slt
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entry:
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%length = load i32* %buffer, !range !0
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%entry.pred = icmp eq i32 %length, 0
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br i1 %entry.pred, label %abort, label %loop.preheader
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loop.preheader:
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br label %loop
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loop:
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; CHECK: loop
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%idx = phi i32 [ %idx.inc, %loop.next ], [ 0, %loop.preheader ]
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%oob.pred = icmp slt i32 %idx, %length
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br i1 %oob.pred, label %loop.next, label %oob
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; CHECK: br i1 true, label %loop.next, label %oob
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loop.next:
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; CHECK: loop.next
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%idx.inc = add i32 %idx, 1
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%exit.pred = icmp slt i32 %idx.inc, %length
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br i1 %exit.pred, label %loop, label %abort.loopexit
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abort.loopexit:
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br label %abort
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abort:
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ret i1 false
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oob:
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tail call void @abort()
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ret i1 false
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}
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define i1 @bounded_below_sle(i32* nocapture readonly %buffer) {
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; CHECK-LABEL: bounded_below_sle
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entry:
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%length = load i32* %buffer, !range !0
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%entry.pred = icmp eq i32 %length, 0
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br i1 %entry.pred, label %abort, label %loop.preheader
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loop.preheader:
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br label %loop
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loop:
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; CHECK: loop
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%idx = phi i32 [ %idx.inc, %loop.next ], [ 0, %loop.preheader ]
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%oob.pred = icmp sle i32 %idx, %length
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br i1 %oob.pred, label %loop.next, label %oob
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; CHECK: br i1 true, label %loop.next, label %oob
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loop.next:
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; CHECK: loop.next
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%idx.inc = add i32 %idx, 1
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%exit.pred = icmp sle i32 %idx.inc, %length
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br i1 %exit.pred, label %loop, label %abort.loopexit
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abort.loopexit:
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br label %abort
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abort:
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ret i1 false
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oob:
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tail call void @abort()
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ret i1 false
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}
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;; Assert that we're not making an incorrect transform.
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declare i32 @check(i8*)
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define void @NoChange() {
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; CHECK-LABEL: NoChange
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entry:
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br label %loop.begin
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loop.begin:
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; CHECK: loop.begin:
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%i.01 = phi i64 [ 2, %entry ], [ %add, %loop.end ]
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%cmp = icmp ugt i64 %i.01, 1
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; CHECK: %cmp = icmp ugt i64 %i.01, 1
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br i1 %cmp, label %loop, label %loop.end
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loop:
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; CHECK: loop
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%.sum = add i64 %i.01, -2
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%v = getelementptr inbounds i8* null, i64 %.sum
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%r = tail call i32 @check(i8* %v)
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%c = icmp eq i32 %r, 0
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br i1 %c, label %loop.end, label %abort.now
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abort.now:
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tail call void @abort()
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unreachable
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loop.end:
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%add = add i64 %i.01, -1
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%eq = icmp eq i64 %add, 0
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br i1 %eq, label %exit, label %loop.begin
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exit:
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ret void
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}
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!0 = metadata !{i32 0, i32 100}
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