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llvm-mirror/test/Transforms/ADCE/2003-06-24-BasicFunctionality.ll
David Callahan 86eb682529 [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

llvm-svn: 289548
2016-12-13 16:42:18 +00:00

45 lines
1.9 KiB
LLVM

; RUN: opt < %s -adce -S | FileCheck %s
; RUN: opt < %s -adce -adce-remove-loops -S | FileCheck %s
define void @dead_test8(i32* %data.1, i32 %idx.1) {
entry:
%tmp.1 = load i32, i32* %data.1 ; <i32> [#uses=2]
%tmp.41 = icmp sgt i32 %tmp.1, 0 ; <i1> [#uses=1]
br i1 %tmp.41, label %no_exit.preheader, label %return
no_exit.preheader: ; preds = %entry
%tmp.11 = getelementptr i32, i32* %data.1, i64 1 ; <i32*> [#uses=1]
%tmp.22-idxcast = sext i32 %idx.1 to i64 ; <i64> [#uses=1]
%tmp.28 = getelementptr i32, i32* %data.1, i64 %tmp.22-idxcast ; <i32*> [#uses=1]
br label %no_exit
no_exit: ; preds = %endif, %no_exit.preheader
%k.1 = phi i32 [ %k.0, %endif ], [ 0, %no_exit.preheader ] ; <i32> [#uses=3]
%i.0 = phi i32 [ %inc.1, %endif ], [ 0, %no_exit.preheader ] ; <i32> [#uses=1]
%tmp.12 = load i32, i32* %tmp.11 ; <i32> [#uses=1]
%tmp.14 = sub i32 0, %tmp.12 ; <i32> [#uses=1]
; CHECK-NOT: %tmp.161
%tmp.161 = icmp ne i32 %k.1, %tmp.14 ; <i1> [#uses=1]
; CHECK: br label %then
br i1 %tmp.161, label %then, label %else
then: ; preds = %no_exit
%inc.0 = add i32 %k.1, 1 ; <i32> [#uses=1]
br label %endif
else: ; preds = %no_exit
%dec = add i32 %k.1, -1 ; <i32> [#uses=1]
br label %endif
endif: ; preds = %else, %then
%k.0 = phi i32 [ %dec, %else ], [ %inc.0, %then ] ; <i32> [#uses=1]
store i32 2, i32* %tmp.28
%inc.1 = add i32 %i.0, 1 ; <i32> [#uses=2]
%tmp.4 = icmp slt i32 %inc.1, %tmp.1 ; <i1> [#uses=1]
br i1 %tmp.4, label %no_exit, label %return
return: ; preds = %endif, %entry
ret void
}