; RUN: opt < %s -passes='print<block-freq>' -disable-output 2>&1 | FileCheck %s ; This code contains three loops. One is triple-nested, the ; second is double nested and the third is a single loop. At ; runtime, all three loops execute 1,000,000 times each. We use to ; give different frequencies to each of the loops because loop ; scales were limited to no more than 4,096. ; ; This was penalizing the hotness of the second and third loops ; because BFI was reducing the loop scale for for.cond16 and ; for.cond26 to a max of 4,096. ; ; Without this restriction, all loops are now correctly given the same ; frequency values. ; ; Original C code: ; ; ; int g; ; __attribute__((noinline)) void bar() { ; g++; ; } ; ; extern int printf(const char*, ...); ; ; int main() ; { ; int i, j, k; ; ; g = 0; ; for (i = 0; i < 100; i++) ; for (j = 0; j < 100; j++) ; for (k = 0; k < 100; k++) ; bar(); ; ; printf ("g = %d\n", g); ; g = 0; ; ; for (i = 0; i < 100; i++) ; for (j = 0; j < 10000; j++) ; bar(); ; ; printf ("g = %d\n", g); ; g = 0; ; ; ; for (i = 0; i < 1000000; i++) ; bar(); ; ; printf ("g = %d\n", g); ; g = 0; ; } @g = common global i32 0, align 4 @.str = private unnamed_addr constant [8 x i8] c"g = %d\0A\00", align 1 declare void @bar() declare i32 @printf(i8*, ...) ; CHECK: Printing analysis {{.*}} for function 'main': ; CHECK-NEXT: block-frequency-info: main define i32 @main() { entry: %retval = alloca i32, align 4 %i = alloca i32, align 4 %j = alloca i32, align 4 %k = alloca i32, align 4 store i32 0, i32* %retval store i32 0, i32* @g, align 4 store i32 0, i32* %i, align 4 br label %for.cond for.cond: ; preds = %for.inc10, %entry %0 = load i32, i32* %i, align 4 %cmp = icmp slt i32 %0, 100 br i1 %cmp, label %for.body, label %for.end12, !prof !1 for.body: ; preds = %for.cond store i32 0, i32* %j, align 4 br label %for.cond1 for.cond1: ; preds = %for.inc7, %for.body %1 = load i32, i32* %j, align 4 %cmp2 = icmp slt i32 %1, 100 br i1 %cmp2, label %for.body3, label %for.end9, !prof !2 for.body3: ; preds = %for.cond1 store i32 0, i32* %k, align 4 br label %for.cond4 for.cond4: ; preds = %for.inc, %for.body3 %2 = load i32, i32* %k, align 4 %cmp5 = icmp slt i32 %2, 100 br i1 %cmp5, label %for.body6, label %for.end, !prof !3 ; CHECK: - for.body6: float = 500000.5, int = 4000004 for.body6: ; preds = %for.cond4 call void @bar() br label %for.inc for.inc: ; preds = %for.body6 %3 = load i32, i32* %k, align 4 %inc = add nsw i32 %3, 1 store i32 %inc, i32* %k, align 4 br label %for.cond4 for.end: ; preds = %for.cond4 br label %for.inc7 for.inc7: ; preds = %for.end %4 = load i32, i32* %j, align 4 %inc8 = add nsw i32 %4, 1 store i32 %inc8, i32* %j, align 4 br label %for.cond1 for.end9: ; preds = %for.cond1 br label %for.inc10 for.inc10: ; preds = %for.end9 %5 = load i32, i32* %i, align 4 %inc11 = add nsw i32 %5, 1 store i32 %inc11, i32* %i, align 4 br label %for.cond for.end12: ; preds = %for.cond %6 = load i32, i32* @g, align 4 %call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i32 0, i32 0), i32 %6) store i32 0, i32* @g, align 4 store i32 0, i32* %i, align 4 br label %for.cond13 for.cond13: ; preds = %for.inc22, %for.end12 %7 = load i32, i32* %i, align 4 %cmp14 = icmp slt i32 %7, 100 br i1 %cmp14, label %for.body15, label %for.end24, !prof !1 for.body15: ; preds = %for.cond13 store i32 0, i32* %j, align 4 br label %for.cond16 for.cond16: ; preds = %for.inc19, %for.body15 %8 = load i32, i32* %j, align 4 %cmp17 = icmp slt i32 %8, 10000 br i1 %cmp17, label %for.body18, label %for.end21, !prof !4 ; CHECK: - for.body18: float = 499999.9, int = 3999998 for.body18: ; preds = %for.cond16 call void @bar() br label %for.inc19 for.inc19: ; preds = %for.body18 %9 = load i32, i32* %j, align 4 %inc20 = add nsw i32 %9, 1 store i32 %inc20, i32* %j, align 4 br label %for.cond16 for.end21: ; preds = %for.cond16 br label %for.inc22 for.inc22: ; preds = %for.end21 %10 = load i32, i32* %i, align 4 %inc23 = add nsw i32 %10, 1 store i32 %inc23, i32* %i, align 4 br label %for.cond13 for.end24: ; preds = %for.cond13 %11 = load i32, i32* @g, align 4 %call25 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i32 0, i32 0), i32 %11) store i32 0, i32* @g, align 4 store i32 0, i32* %i, align 4 br label %for.cond26 for.cond26: ; preds = %for.inc29, %for.end24 %12 = load i32, i32* %i, align 4 %cmp27 = icmp slt i32 %12, 1000000 br i1 %cmp27, label %for.body28, label %for.end31, !prof !5 ; CHECK: - for.body28: float = 499995.2, int = 3999961 for.body28: ; preds = %for.cond26 call void @bar() br label %for.inc29 for.inc29: ; preds = %for.body28 %13 = load i32, i32* %i, align 4 %inc30 = add nsw i32 %13, 1 store i32 %inc30, i32* %i, align 4 br label %for.cond26 for.end31: ; preds = %for.cond26 %14 = load i32, i32* @g, align 4 %call32 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([8 x i8], [8 x i8]* @.str, i32 0, i32 0), i32 %14) store i32 0, i32* @g, align 4 %15 = load i32, i32* %retval ret i32 %15 } !llvm.ident = !{!0} !0 = !{!"clang version 3.7.0 (trunk 232635) (llvm/trunk 232636)"} !1 = !{!"branch_weights", i32 101, i32 2} !2 = !{!"branch_weights", i32 10001, i32 101} !3 = !{!"branch_weights", i32 1000001, i32 10001} !4 = !{!"branch_weights", i32 1000001, i32 101} !5 = !{!"branch_weights", i32 1000001, i32 2}