153 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
			
		
		
	
	
			153 lines
		
	
	
		
			5.3 KiB
		
	
	
	
		
			LLVM
		
	
	
	
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=1 -S < %s                    | FileCheck %s --check-prefix=HOIST
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; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -hoist-common-insts=0 -S < %s                    | FileCheck %s --check-prefix=NOHOIST
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; RUN: opt -simplifycfg -simplifycfg-require-and-preserve-domtree=1                       -S < %s                    | FileCheck %s --check-prefix=NOHOIST
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; This example is produced from a very basic C code:
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;
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;   void f0();
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;   void f1();
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;   void f2();
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;
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;   void loop(int width) {
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;       if(width < 1)
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;           return;
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;       for(int i = 0; i < width - 1;+i) {
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;           f0();
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;           f1();
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;       }
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;       f0();
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;       f2();
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;   }
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; We have a choice here. We can either
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; * hoist the f0() call into loop header,
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;   * which potentially makes loop rotation unprofitable since loop header might
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;     have grown above certain threshold, and such unrotated loops will be
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;     ignored by LoopVectorizer, preventing vectorization
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;   * or loop rotation will succeed, resulting in some weird PHIs that will also
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;     harm vectorization
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; * or not hoist f0() call before performing loop rotation,
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;   at the cost of potential code bloat and/or potentially successfully rotating
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;   the loops, vectorizing them at the cost of compile time.
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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declare i1 @gen1()
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declare void @f0()
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declare void @f1()
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declare void @f2()
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declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture)
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declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture)
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define void @_Z4loopi(i1 %cmp) {
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; HOIST-LABEL: @_Z4loopi(
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; HOIST-NEXT:  entry:
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; HOIST-NEXT:    br i1 [[CMP:%.*]], label [[RETURN:%.*]], label [[FOR_COND:%.*]]
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; HOIST:       for.cond:
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; HOIST-NEXT:    [[CMP1:%.*]] = call i1 @gen1()
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; HOIST-NEXT:    call void @f0()
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; HOIST-NEXT:    br i1 [[CMP1]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
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; HOIST:       for.body:
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; HOIST-NEXT:    call void @f1()
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; HOIST-NEXT:    br label [[FOR_COND]]
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; HOIST:       for.end:
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; HOIST-NEXT:    call void @f2()
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; HOIST-NEXT:    br label [[RETURN]]
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; HOIST:       return:
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; HOIST-NEXT:    ret void
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;
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; NOHOIST-LABEL: @_Z4loopi(
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; NOHOIST-NEXT:  entry:
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; NOHOIST-NEXT:    br i1 [[CMP:%.*]], label [[RETURN:%.*]], label [[FOR_COND:%.*]]
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; NOHOIST:       for.cond:
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; NOHOIST-NEXT:    [[CMP1:%.*]] = call i1 @gen1()
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; NOHOIST-NEXT:    br i1 [[CMP1]], label [[FOR_BODY:%.*]], label [[FOR_END:%.*]]
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; NOHOIST:       for.body:
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; NOHOIST-NEXT:    call void @f0()
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; NOHOIST-NEXT:    call void @f1()
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; NOHOIST-NEXT:    br label [[FOR_COND]]
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; NOHOIST:       for.end:
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; NOHOIST-NEXT:    call void @f0()
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; NOHOIST-NEXT:    call void @f2()
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; NOHOIST-NEXT:    br label [[RETURN]]
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; NOHOIST:       return:
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; NOHOIST-NEXT:    ret void
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;
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entry:
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  br i1 %cmp, label %if.then, label %if.end
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if.then:
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  br label %return
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if.end:
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  br label %for.cond
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for.cond:
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  %cmp1 = call i1 @gen1()
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  br i1 %cmp1, label %for.body, label %for.cond.cleanup
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for.cond.cleanup:
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  br label %for.end
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for.body:
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  call void @f0()
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  call void @f1()
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  br label %for.inc
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for.inc:
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  br label %for.cond
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for.end:
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  call void @f0()
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  call void @f2()
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  br label %return
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return:
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  ret void
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}
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; A example where only the branch instructions from %if.then2 and %if.end3 need
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; to be hoisted, which effectively replaces the original branch in %if.end and
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; only requires selects for PHIs in the successor.
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define float @clamp_float_value(float %value, float %minimum_value, float %maximum_value) {
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; HOIST-LABEL: @clamp_float_value(
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; HOIST-NEXT:  entry:
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; HOIST-NEXT:    [[CMP:%.*]] = fcmp ogt float [[VALUE:%.*]], [[MAXIMUM_VALUE:%.*]]
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; HOIST-NEXT:    [[CMP1:%.*]] = fcmp olt float [[VALUE]], [[MINIMUM_VALUE:%.*]]
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; HOIST-NEXT:    [[MINIMUM_VALUE_VALUE:%.*]] = select i1 [[CMP1]], float [[MINIMUM_VALUE]], float [[VALUE]]
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; HOIST-NEXT:    [[RETVAL_0:%.*]] = select i1 [[CMP]], float [[MAXIMUM_VALUE]], float [[MINIMUM_VALUE_VALUE]]
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; HOIST-NEXT:    ret float [[RETVAL_0]]
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;
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; NOHOIST-LABEL: @clamp_float_value(
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; NOHOIST-NEXT:  entry:
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; NOHOIST-NEXT:    [[CMP:%.*]] = fcmp ogt float [[VALUE:%.*]], [[MAXIMUM_VALUE:%.*]]
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; NOHOIST-NEXT:    [[CMP1:%.*]] = fcmp olt float [[VALUE]], [[MINIMUM_VALUE:%.*]]
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; NOHOIST-NEXT:    [[MINIMUM_VALUE_VALUE:%.*]] = select i1 [[CMP1]], float [[MINIMUM_VALUE]], float [[VALUE]]
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; NOHOIST-NEXT:    [[RETVAL_0:%.*]] = select i1 [[CMP]], float [[MAXIMUM_VALUE]], float [[MINIMUM_VALUE_VALUE]]
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; NOHOIST-NEXT:    ret float [[RETVAL_0]]
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;
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entry:
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  %cmp = fcmp ogt float %value, %maximum_value
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  br i1 %cmp, label %if.then, label %if.end
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if.then:                                          ; preds = %entry
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  br label %return
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if.end:                                           ; preds = %entry
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  %cmp1 = fcmp olt float %value, %minimum_value
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  br i1 %cmp1, label %if.then2, label %if.end3
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if.then2:                                         ; preds = %if.end
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  br label %return
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if.end3:                                          ; preds = %if.end
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  br label %return
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return:                                           ; preds = %if.end3, %if.then2, %if.then
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  %retval.0 = phi float [ %maximum_value, %if.then ], [ %minimum_value, %if.then2 ], [ %value, %if.end3 ]
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  ret float %retval.0
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}
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