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llvm-mirror/test/Analysis/LazyValueAnalysis/lvi-after-jumpthreading.ll
Brian M. Rzycki 504eb62dfb [JumpThreading] Preservation of DT and LVI across the pass
Summary:
See D37528 for a previous (non-deferred) version of this
patch and its description.

Preserves dominance in a deferred manner using a new class
DeferredDominance. This reduces the performance impact of
updating the DominatorTree at every edge insertion and
deletion. A user may call DDT->flush() within JumpThreading
for an up-to-date DT. This patch currently has one flush()
at the end of runImpl() to ensure DT is preserved across
the pass.

LVI is also preserved to help subsequent passes such as
CorrelatedValuePropagation. LVI is simpler to maintain and
is done immediately (not deferred). The code to perform the
preversation was minimally altered and simply marked as
preserved for the PassManager to be informed.

This extends the analysis available to JumpThreading for
future enhancements such as threading across loop headers.

Reviewers: dberlin, kuhar, sebpop

Reviewed By: kuhar, sebpop

Subscribers: mgorny, dmgreen, kuba, rnk, rsmith, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D40146

llvm-svn: 322401
2018-01-12 21:06:48 +00:00

190 lines
8.1 KiB
LLVM

; RUN: opt < %s -jump-threading -print-lvi-after-jump-threading -disable-output 2>&1 | FileCheck %s
; Testing LVI cache after jump-threading
; Jump-threading transforms the IR below to one where
; loop and backedge basic blocks are merged into one.
; basic block (named backedge) with the branch being:
; %cont = icmp slt i32 %iv.next, 400
; br i1 %cont, label %backedge, label %exit
define i8 @test1(i32 %a, i32 %length) {
; CHECK-LABEL: LVI for function 'test1':
entry:
; CHECK-LABEL: entry:
; CHECK-NEXT: ; LatticeVal for: 'i32 %a' is: overdefined
; CHECK-NEXT: ; LatticeVal for: 'i32 %length' is: overdefined
br label %loop
; CHECK-LABEL: backedge:
; CHECK-NEXT: ; LatticeVal for: 'i32 %a' is: overdefined
; CHECK-NEXT: ; LatticeVal for: 'i32 %length' is: overdefined
; CHECK-NEXT: ; LatticeVal for: ' %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%backedge' is: constantrange<0, 400>
; CHECK-NEXT: ; LatticeVal for: ' %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%exit' is: constantrange<399, 400>
; CHECK-NEXT: %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
; CHECK-NEXT: ; LatticeVal for: ' %iv.next = add nsw i32 %iv, 1' in BB: '%backedge' is: constantrange<1, 401>
; CHECK-NEXT: ; LatticeVal for: ' %iv.next = add nsw i32 %iv, 1' in BB: '%exit' is: constantrange<400, 401>
; CHECK-NEXT: %iv.next = add nsw i32 %iv, 1
; CHECK-NEXT: ; LatticeVal for: ' %cont = icmp slt i32 %iv.next, 400' in BB: '%backedge' is: overdefined
; CHECK-NEXT: ; LatticeVal for: ' %cont = icmp slt i32 %iv.next, 400' in BB: '%exit' is: constantrange<0, -1>
; CHECK-NEXT: %cont = icmp slt i32 %iv.next, 400
; CHECK-NOT: loop
loop:
%iv = phi i32 [0, %entry], [%iv.next, %backedge]
%cnd = icmp sge i32 %iv, 0
br i1 %cnd, label %backedge, label %exit
backedge:
%iv.next = add nsw i32 %iv, 1
%cont = icmp slt i32 %iv.next, 400
br i1 %cont, label %loop, label %exit
exit:
ret i8 0
}
; Here JT does not transform the code, but LVICache is populated during the processing of blocks.
define i8 @test2(i32 %n) {
; CHECK-LABEL: LVI for function 'test2':
; CHECK-LABEL: entry:
; CHECK-NEXT: ; LatticeVal for: 'i32 %n' is: overdefined
; CHECK-NEXT: br label %loop
entry:
br label %loop
; CHECK-LABEL: loop:
; CHECK-NEXT: ; LatticeVal for: 'i32 %n' is: overdefined
; CHECK-NEXT: ; LatticeVal for: ' %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%loop' is: constantrange<0, -2147483647>
; CHECK-DAG: ; LatticeVal for: ' %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%backedge' is: constantrange<0, -2147483648>
; CHECK-DAG: ; LatticeVal for: ' %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]' in BB: '%exit' is: constantrange<0, -2147483647>
; CHECK-NEXT: %iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ]
loop:
%iv = phi i32 [0, %entry], [%iv.next, %backedge]
; CHECK-NEXT: ; LatticeVal for: ' %iv2 = phi i32 [ %n, %entry ], [ %iv2.next, %backedge ]' in BB: '%loop' is: overdefined
; CHECK-DAG: ; LatticeVal for: ' %iv2 = phi i32 [ %n, %entry ], [ %iv2.next, %backedge ]' in BB: '%backedge' is: constantrange<1, -2147483648>
; CHECK-DAG: ; LatticeVal for: ' %iv2 = phi i32 [ %n, %entry ], [ %iv2.next, %backedge ]' in BB: '%exit' is: overdefined
; CHECK-NEXT: %iv2 = phi i32 [ %n, %entry ], [ %iv2.next, %backedge ]
%iv2 = phi i32 [%n, %entry], [%iv2.next, %backedge]
; CHECK-NEXT: ; LatticeVal for: ' %cnd1 = icmp sge i32 %iv, 0' in BB: '%loop' is: overdefined
; CHECK-DAG: ; LatticeVal for: ' %cnd1 = icmp sge i32 %iv, 0' in BB: '%backedge' is: overdefined
; CHECK-DAG: ; LatticeVal for: ' %cnd1 = icmp sge i32 %iv, 0' in BB: '%exit' is: overdefined
; CHECK-NEXT: %cnd1 = icmp sge i32 %iv, 0
%cnd1 = icmp sge i32 %iv, 0
%cnd2 = icmp sgt i32 %iv2, 0
; CHECK: %cnd2 = icmp sgt i32 %iv2, 0
; CHECK: ; LatticeVal for: ' %cnd = and i1 %cnd1, %cnd2' in BB: '%loop' is: overdefined
; CHECK-DAG: ; LatticeVal for: ' %cnd = and i1 %cnd1, %cnd2' in BB: '%backedge' is: constantrange<-1, 0>
; CHECK-DAG: ; LatticeVal for: ' %cnd = and i1 %cnd1, %cnd2' in BB: '%exit' is: overdefined
; CHECK-NEXT: %cnd = and i1 %cnd1, %cnd2
%cnd = and i1 %cnd1, %cnd2
br i1 %cnd, label %backedge, label %exit
; CHECK-LABEL: backedge:
; CHECK-NEXT: ; LatticeVal for: 'i32 %n' is: overdefined
; CHECK-NEXT: ; LatticeVal for: ' %iv.next = add nsw i32 %iv, 1' in BB: '%backedge' is: constantrange<1, -2147483647>
; CHECK-NEXT: %iv.next = add nsw i32 %iv, 1
backedge:
%iv.next = add nsw i32 %iv, 1
%iv2.next = sub nsw i32 %iv2, 1
; CHECK: ; LatticeVal for: ' %cont1 = icmp slt i32 %iv.next, 400' in BB: '%backedge' is: overdefined
; CHECK-NEXT: %cont1 = icmp slt i32 %iv.next, 400
%cont1 = icmp slt i32 %iv.next, 400
; CHECK-NEXT: ; LatticeVal for: ' %cont2 = icmp sgt i32 %iv2.next, 0' in BB: '%backedge' is: overdefined
; CHECK-NEXT: %cont2 = icmp sgt i32 %iv2.next, 0
%cont2 = icmp sgt i32 %iv2.next, 0
; CHECK-NEXT: ; LatticeVal for: ' %cont = and i1 %cont1, %cont2' in BB: '%backedge' is: overdefined
; CHECK-NEXT: %cont = and i1 %cont1, %cont2
%cont = and i1 %cont1, %cont2
br i1 %cont, label %loop, label %exit
exit:
ret i8 0
}
; Merging cont block into do block. Make sure that we do not incorrectly have the cont
; LVI info as LVI info for the beginning of do block. LVI info for %i is Range[0,1)
; at beginning of cont Block, which is incorrect at the beginning of do block.
define i32 @test3(i32 %i, i1 %f, i32 %n) {
; CHECK-LABEL: LVI for function 'test3':
; CHECK-LABEL: entry
; CHECK: ; LatticeVal for: 'i32 %i' is: overdefined
; CHECK: %c = icmp ne i32 %i, -2134
; CHECK: br i1 %c, label %cont, label %exit
entry:
%c = icmp ne i32 %i, -2134
br i1 %c, label %do, label %exit
exit:
%c1 = icmp ne i32 %i, -42
br i1 %c1, label %exit2, label %exit
; CHECK-LABEL: cont:
; Here cont is merged to do and i is any value except -2134.
; i is not the single value: zero.
; CHECK-NOT: ; LatticeVal for: 'i32 %i' is: constantrange<0, 1>
; CHECK: ; LatticeVal for: 'i32 %i' is: constantrange<-2133, -2134>
; CHECK: ; LatticeVal for: ' %cond.0 = icmp sgt i32 %i, 0' in BB: '%cont' is: overdefined
; CHECK: %cond.0 = icmp sgt i32 %i, 0
; CHECK: %consume = call i32 @consume
; CHECK: %cond = icmp eq i32 %i, 0
; CHECK: call void (i1, ...) @llvm.experimental.guard(i1 %cond)
; CHECK: %cond.3 = icmp sgt i32 %i, %n
; CHECK: br i1 %cond.3, label %exit2, label %exit
cont:
%cond.3 = icmp sgt i32 %i, %n
br i1 %cond.3, label %exit2, label %exit
do:
%cond.0 = icmp sgt i32 %i, 0
%consume = call i32 @consume(i1 %cond.0)
%cond = icmp eq i32 %i, 0
call void (i1, ...) @llvm.experimental.guard(i1 %cond) [ "deopt"() ]
%cond.2 = icmp sgt i32 %i, 0
br i1 %cond.2, label %exit, label %cont
exit2:
; CHECK-LABEL: exit2:
; LatticeVal for: 'i32 %i' is: constantrange<-2134, 1>
ret i32 30
}
; FIXME: We should be able to merge cont into do.
; When we do so, LVI for cont cannot be the one for the merged do block.
define i32 @test4(i32 %i, i1 %f, i32 %n) {
; CHECK-LABEL: LVI for function 'test4':
entry:
%c = icmp ne i32 %i, -2134
br i1 %c, label %do, label %exit
exit: ; preds = %do, %cont, %exit, %entry
%c1 = icmp ne i32 %i, -42
br i1 %c1, label %exit2, label %exit
cont: ; preds = %do
; CHECK-LABEL: cont:
; CHECK: ; LatticeVal for: 'i1 %f' is: constantrange<-1, 0>
; CHECK: call void @dummy(i1 %f)
call void @dummy(i1 %f)
br label %exit2
do: ; preds = %entry
; CHECK-LABEL: do:
; CHECK: ; LatticeVal for: 'i1 %f' is: overdefined
; CHECK: call void @dummy(i1 %f)
; CHECK: br i1 %cond, label %exit, label %cont
call void @dummy(i1 %f)
%consume = call i32 @exit()
call void @llvm.assume(i1 %f)
%cond = icmp eq i1 %f, false
br i1 %cond, label %exit, label %cont
exit2: ; preds = %cont, %exit
ret i32 30
}
declare i32 @exit()
declare i32 @consume(i1)
declare void @llvm.assume(i1) nounwind
declare void @dummy(i1) nounwind
declare void @llvm.experimental.guard(i1, ...)