llvm/test/Transforms/ADCE/2016-09-06.ll
David Callahan 520236e36f [ADCE] Add code to remove dead branches
Summary:
This is last in of a series of patches to evolve ADCE.cpp to support
removing of unnecessary control flow.

This patch adds the code to update the control and data flow graphs
to remove the dead control flow.

Also update unit tests to test the capability to remove dead,
may-be-infinite loop which is enabled by the switch
-adce-remove-loops.

Previous patches:

D23824 [ADCE] Add handling of PHI nodes when removing control flow
D23559 [ADCE] Add control dependence computation
D23225 [ADCE] Modify data structures to support removing control flow
D23065 [ADCE] Refactor anticipating new functionality (NFC)
D23102 [ADCE] Refactoring for new functionality (NFC)

Reviewers: dberlin, majnemer, nadav, mehdi_amini

Subscribers: llvm-commits, david2050, freik, twoh

Differential Revision: https://reviews.llvm.org/D24918

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@289548 91177308-0d34-0410-b5e6-96231b3b80d8
2016-12-13 16:42:18 +00:00

56 lines
1.7 KiB
LLVM

; RUN: opt < %s -sroa -adce -adce-remove-loops -S | FileCheck %s
; ModuleID = 'test1.bc'
source_filename = "test1.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
; Function Attrs: nounwind uwtable
define i32 @foo(i32, i32, i32) #0 {
%4 = alloca i32, align 4
%5 = alloca i32, align 4
%6 = alloca i32, align 4
%7 = alloca i32, align 4
%8 = alloca i32, align 4
store i32 %0, i32* %4, align 4
store i32 %1, i32* %5, align 4
store i32 %2, i32* %6, align 4
store i32 0, i32* %7, align 4
%9 = load i32, i32* %5, align 4
%I10 = icmp ne i32 %9, 0
br i1 %I10, label %B11, label %B21
B11:
store i32 0, i32* %8, align 4
br label %B12
B12:
%I13 = load i32, i32* %8, align 4
%I14 = load i32, i32* %6, align 4
%I15 = icmp slt i32 %I13, %I14
; CHECK: br label %B20
br i1 %I15, label %B16, label %B20
B16:
br label %B17
B17:
%I18 = load i32, i32* %8, align 4
%I19 = add nsw i32 %I18, 1
store i32 %I19, i32* %8, align 4
br label %B12
B20:
store i32 1, i32* %7, align 4
br label %B21
B21:
%I22 = load i32, i32* %7, align 4
ret i32 %I22
}
attributes #0 = { nounwind uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.ident = !{!0}
!0 = !{!"clang version 4.0.0 (http://llvm.org/git/clang.git 5864a13abf4490e76ae2eb0896198e1305927df2)"}