[llvm] 3de4166 - [NFC][SimplifyCFG] Add standalone test for common code hoisting xform option

[Roman Lebedev via llvm-commits]

Author: Roman Lebedev
Date: 2020-07-20T10:29:29+03:00
New Revision: 3de41663251941e4c12ceb3b12b5d43c54a27a24

URL: https://github.com/llvm/llvm-project/commit/3de41663251941e4c12ceb3b12b5d43c54a27a24
DIFF: https://github.com/llvm/llvm-project/commit/3de41663251941e4c12ceb3b12b5d43c54a27a24.diff

LOG: [NFC][SimplifyCFG] Add standalone test for common code hoisting xform option

Also, move one test into it's correct place

Added: 
    llvm/test/Transforms/SimplifyCFG/X86/pr39187-g.ll
    llvm/test/Transforms/SimplifyCFG/common-code-hoisting.ll

Modified: 
    

Removed: 
    llvm/test/CodeGen/X86/pr39187-g.ll


################################################################################
diff  --git a/llvm/test/CodeGen/X86/pr39187-g.ll b/llvm/test/Transforms/SimplifyCFG/X86/pr39187-g.ll
similarity index 100%
rename from llvm/test/CodeGen/X86/pr39187-g.ll
rename to llvm/test/Transforms/SimplifyCFG/X86/pr39187-g.ll

diff  --git a/llvm/test/Transforms/SimplifyCFG/common-code-hoisting.ll b/llvm/test/Transforms/SimplifyCFG/common-code-hoisting.ll
new file mode 100644
index 000000000000..c44676bdf0cc
--- /dev/null
+++ b/llvm/test/Transforms/SimplifyCFG/common-code-hoisting.ll
@@ -0,0 +1,91 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -simplifycfg                       -S < %s                    | FileCheck %s --check-prefixes=HOIST,DEFAULT
+
+; This example is produced from a very basic C code:
+;
+;   void f0();
+;   void f1();
+;   void f2();
+;
+;   void loop(int width) {
+;       if(width < 1)
+;           return;
+;       for(int i = 0; i < width - 1; ++i) {
+;           f0();
+;           f1();
+;       }
+;       f0();
+;       f2();
+;   }
+
+; We have a choice here. We can either
+; * hoist the f0() call into loop header,
+;   * which potentially makes loop rotation unprofitable since loop header might
+;     have grown above certain threshold, and such unrotated loops will be
+;     ignored by LoopVectorizer, preventing vectorization
+;   * or loop rotation will succeed, resulting in some weird PHIs that will also
+;     harm vectorization
+; * or not hoist f0() call before performing loop rotation,
+;   at the cost of potential code bloat and/or potentially successfully rotating
+;   the loops, vectorizing them at the cost of compile time.
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+
+declare i1 @gen1()
+
+declare void @f0()
+declare void @f1()
+declare void @f2()
+
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
+declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
+
+define void @_Z4loopi(i1 %cmp) {
+; HOIST-LABEL: @_Z4loopi(
+; HOIST-NEXT:  entry:
+; HOIST-NEXT:    br i1 [[CMP:%.*]], label [[RETURN:%.*]], label [[FOR_COND:%.*]]
+; HOIST:       for.cond:
+; HOIST-NEXT:    [[CMP1:%.*]] = call i1 @gen1()
+; HOIST-NEXT:    call void @f0()
+; HOIST-NEXT:    br i1 [[CMP1]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
+; HOIST:       for.body:
+; HOIST-NEXT:    call void @f1()
+; HOIST-NEXT:    br label [[FOR_COND]]
+; HOIST:       for.end:
+; HOIST-NEXT:    call void @f2()
+; HOIST-NEXT:    br label [[RETURN]]
+; HOIST:       return:
+; HOIST-NEXT:    ret void
+;
+entry:
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+  br label %return
+
+if.end:
+  br label %for.cond
+
+for.cond:
+  %cmp1 = call i1 @gen1()
+  br i1 %cmp1, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup:
+  br label %for.end
+
+for.body:
+  call void @f0()
+  call void @f1()
+  br label %for.inc
+
+for.inc:
+  br label %for.cond
+
+for.end:
+  call void @f0()
+  call void @f2()
+  br label %return
+
+return:
+  ret void
+}