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254b813ec2
Summary: Constant fold switch inst when looking for trivial conditions to unswitch on. Reviewers: sanjoy, chenli, hfinkel, efriedma Subscribers: llvm-commits, mzolotukhin Differential Revision: https://reviews.llvm.org/D29037 llvm-svn: 293250
92 lines
3.0 KiB
LLVM
92 lines
3.0 KiB
LLVM
; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -verify-loop-info -S < %s 2>&1 | FileCheck %s
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; This test contains two trivial unswitch condition in one loop.
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; LoopUnswitch pass should be able to unswitch the second one
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; after unswitching the first one.
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; CHECK: br i1 %cond1, label %..split_crit_edge, label %.loop_exit.split_crit_edge
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; CHECK: ..split_crit_edge: ; preds = %0
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; CHECK: br label %.split
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; CHECK: .split: ; preds = %..split_crit_edge
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; CHECK: br i1 %cond2, label %.split..split.split_crit_edge, label %.split.loop_exit.split1_crit_edge
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; CHECK: .split..split.split_crit_edge: ; preds = %.split
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; CHECK: br label %.split.split
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; CHECK: .split.split: ; preds = %.split..split.split_crit_edge
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; CHECK: br label %loop_begin
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; CHECK: loop_begin: ; preds = %do_something, %.split.split
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; CHECK: br i1 true, label %continue, label %loop_exit
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; CHECK: continue: ; preds = %loop_begin
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; CHECK: %var_val = load i32, i32* %var
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; CHECK: br i1 true, label %do_something, label %loop_exit
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define i32 @test(i32* %var, i1 %cond1, i1 %cond2) {
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br label %loop_begin
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loop_begin:
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br i1 %cond1, label %continue, label %loop_exit ; first trivial condition
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continue:
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%var_val = load i32, i32* %var
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br i1 %cond2, label %do_something, label %loop_exit ; second trivial condition
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do_something:
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call void @some_func() noreturn nounwind
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br label %loop_begin
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loop_exit:
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ret i32 0
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}
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; We will not be able trivially unswitch on the SwitchInst, as its input
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; is a constant. However, since its a constant we should be able to figure
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; out that the switch can be folded into a unconditional branch to %continue.
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; Then we unswitch on the br inst in %continue.
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;
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; CHECK: define i32 @test2(
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; This is an indication that the loop has been unswitched on %cond1.
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; CHECK: br i1 %cond1, label %..split_crit_edge, label %.loop_exit.split_crit_edge
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; CHECK: ..split_crit_edge: ; preds = %0
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; CHECK: br label %.split
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; CHECK: .split: ; preds = %..split_crit_edge
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; CHECK: br label %loop_begin
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; CHECK: loop_begin: ; preds = %do_something, %.split
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; CHECK: switch i32
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; CHECK: continue: ; preds = %loop_begin
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; CHECK: %var_val = load i32, i32* %var
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; CHECK: br i1 true, label %do_something, label %loop_exit
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define i32 @test2(i32* %var, i1 %cond1) {
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br label %loop_begin
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loop_begin:
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switch i32 1, label %continue [
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i32 0, label %loop_exit
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i32 1, label %continue
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]
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continue:
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%var_val = load i32, i32* %var
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br i1 %cond1, label %do_something, label %loop_exit
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do_something:
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call void @some_func() noreturn nounwind
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br label %loop_begin
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loop_exit:
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ret i32 0
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}
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declare void @some_func() noreturn
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