loops_with_profile_info.ll
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; RUN: opt < %s -analyze -block-freq -enable-new-pm=0 | FileCheck %s
; 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}