4ab0f4910a
I want to use the same logic as LoopSimplify to form dedicated exits in another pass (SimpleLoopUnswitch) so I wanted to factor it out here. I also noticed that there is a pretty significantly more efficient way to implement this than the way the code in LoopSimplify worked. We don't need to actually retain the set of unique exit blocks, we can just rewrite them as we find them and use only a set to deduplicate. This did require changing one part of LoopSimplify to not re-use the unique set of exits, but it only used it to check that there was a single unique exit. That part of the code is about to walk the exiting blocks anyways, so it seemed better to rewrite it to use those exiting blocks to compute this property on-demand. I also had to ditch a statistic, but it doesn't seem terribly valuable. Differential Revision: https://reviews.llvm.org/D34049 llvm-svn: 306081
95 lines
3.3 KiB
LLVM
95 lines
3.3 KiB
LLVM
; REQUIRES: asserts
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; RUN: opt -loop-unswitch -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
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; RUN: opt -S -loop-unswitch -verify-loop-info -verify-dom-info < %s | FileCheck %s
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; STATS: 2 loop-unswitch - Number of switches unswitched
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; CHECK: %1 = icmp eq i32 %c, 1
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; CHECK-NEXT: br i1 %1, label %.split.us, label %..split_crit_edge
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; CHECK: ..split_crit_edge: ; preds = %0
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; CHECK-NEXT: br label %.split
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; CHECK: .split.us: ; preds = %0
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; CHECK-NEXT: br label %loop_begin.us
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; CHECK: loop_begin.us: ; preds = %loop_begin.backedge.us, %.split.us
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; CHECK-NEXT: %var_val.us = load i32, i32* %var
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; CHECK-NEXT: switch i32 1, label %default.us-lcssa.us [
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; CHECK-NEXT: i32 1, label %inc.us
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; CHECK: inc.us: ; preds = %loop_begin.us
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; CHECK-NEXT: call void @incf() [[NOR_NUW:#[0-9]+]]
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; CHECK-NEXT: br label %loop_begin.backedge.us
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; CHECK: .split: ; preds = %..split_crit_edge
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; CHECK-NEXT: %2 = icmp eq i32 %c, 2
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; CHECK-NEXT: br i1 %2, label %.split.split.us, label %.split..split.split_crit_edge
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; CHECK: .split..split.split_crit_edge: ; preds = %.split
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; CHECK-NEXT: br label %.split.split
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; CHECK: .split.split.us: ; preds = %.split
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; CHECK-NEXT: br label %loop_begin.us1
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; CHECK: loop_begin.us1: ; preds = %loop_begin.backedge.us5, %.split.split.us
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; CHECK-NEXT: %var_val.us2 = load i32, i32* %var
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; CHECK-NEXT: switch i32 2, label %default.us-lcssa.us-lcssa.us [
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; CHECK-NEXT: i32 1, label %inc.us4
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; CHECK-NEXT: i32 2, label %dec.us3
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; CHECK-NEXT: ]
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; CHECK: dec.us3: ; preds = %loop_begin.us1
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; CHECK-NEXT: call void @decf() [[NOR_NUW]]
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; CHECK-NEXT: br label %loop_begin.backedge.us5
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; CHECK: .split.split: ; preds = %.split..split.split_crit_edge
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; CHECK-NEXT: br label %loop_begin
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; CHECK: loop_begin: ; preds = %loop_begin.backedge, %.split.split
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; CHECK-NEXT: %var_val = load i32, i32* %var
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; CHECK-NEXT: switch i32 %c, label %default.us-lcssa.us-lcssa [
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; CHECK-NEXT: i32 1, label %inc
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; CHECK-NEXT: i32 2, label %dec
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; CHECK-NEXT: ]
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; CHECK: inc: ; preds = %loop_begin
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; CHECK-NEXT: br i1 true, label %us-unreachable.us-lcssa, label %inc.split
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; CHECK: dec: ; preds = %loop_begin
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; CHECK-NEXT: br i1 true, label %us-unreachable6, label %dec.split
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define i32 @test(i32* %var) {
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%mem = alloca i32
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store i32 2, i32* %mem
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%c = load i32, i32* %mem
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br label %loop_begin
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loop_begin:
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%var_val = load i32, i32* %var
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switch i32 %c, label %default [
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i32 1, label %inc
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i32 2, label %dec
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]
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inc:
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call void @incf() noreturn nounwind
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br label %loop_begin
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dec:
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call void @decf() noreturn nounwind
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br label %loop_begin
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default:
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br label %loop_exit
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loop_exit:
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ret i32 0
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}
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declare void @incf() noreturn
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declare void @decf() noreturn
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; CHECK: attributes #0 = { noreturn }
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; CHECK: attributes [[NOR_NUW]] = { noreturn nounwind }
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