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llvm-mirror/test/Transforms/SimplifyCFG/PhiBlockMerge2.ll
Roman Lebedev 785059d651 [SimplifyCFG] TryToSimplifyUncondBranchFromEmptyBlock() already knows how to preserve DomTree
... so just ensure that we pass DomTreeUpdater it into it.

Fixes DomTree preservation for a large number of tests,
all of which are marked as such so that they do not regress.
2020-12-17 01:03:49 +03:00

28 lines
611 B
LLVM

; Test merging of blocks that only have PHI nodes in them. This tests the case
; where the mergedinto block doesn't have any PHI nodes, and is in fact
; dominated by the block-to-be-eliminated
;
; RUN: opt < %s -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S | not grep N:
;
declare i1 @foo()
define i32 @test(i1 %a, i1 %b) {
%c = call i1 @foo()
br i1 %c, label %N, label %P
P:
%d = call i1 @foo()
br i1 %d, label %N, label %Q
Q:
br label %N
N:
%W = phi i32 [0, %0], [1, %Q], [2, %P]
; This block should be foldable into M
br label %M
M:
%R = add i32 %W, 1
ret i32 %R
}