[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
diff --git a/llvm/test/Transforms/ADCE/2003-06-24-BasicFunctionality.ll b/llvm/test/Transforms/ADCE/2003-06-24-BasicFunctionality.ll
index f0de431..ac2a30d 100644
--- a/llvm/test/Transforms/ADCE/2003-06-24-BasicFunctionality.ll
+++ b/llvm/test/Transforms/ADCE/2003-06-24-BasicFunctionality.ll
@@ -1,4 +1,5 @@
-; RUN: opt < %s -adce -simplifycfg -S | not grep then:
+; 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:
@@ -17,7 +18,9 @@
%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