; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=1 -S < %s | FileCheck %s --check-prefix=HOIST ; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=0 -S < %s | FileCheck %s --check-prefix=NOHOIST ; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -S < %s | FileCheck %s --check-prefix=NOHOIST ; 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 ; ; NOHOIST-LABEL: @_Z4loopi( ; NOHOIST-NEXT: entry: ; NOHOIST-NEXT: br i1 [[CMP:%.*]], label [[RETURN:%.*]], label [[FOR_COND:%.*]] ; NOHOIST: for.cond: ; NOHOIST-NEXT: [[CMP1:%.*]] = call i1 @gen1() ; NOHOIST-NEXT: br i1 [[CMP1]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]] ; NOHOIST: for.body: ; NOHOIST-NEXT: call void @f0() ; NOHOIST-NEXT: call void @f1() ; NOHOIST-NEXT: br label [[FOR_COND]] ; NOHOIST: for.end: ; NOHOIST-NEXT: call void @f0() ; NOHOIST-NEXT: call void @f2() ; NOHOIST-NEXT: br label [[RETURN]] ; NOHOIST: return: ; NOHOIST-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 }