Leslie Zhai via llvm-dev
2017-Oct-24 04:19 UTC
[llvm-dev] LLVM 6.0's LoopUnroll PASS is not able to work?
Hi LLVM developers,
$ cat hello.c
#include <stdio.h>
int main(int argc, char *argv[]) {
for (int i = 0; i < 10; i++) {
printf("%d\n", i);
}
return 0;
}
$ /opt/llvm-svn/bin/clang --version
Fedora clang version 6.0.0 (trunk 316308) (based on LLVM 6.0.0svn)
Target: x86_64-redhat-linux
Thread model: posix
InstalledDir: /opt/llvm-svn/bin
$ /opt/llvm-svn/bin/clang -S -emit-llvm hello.c -o hello3.ll
$ cat hello3.ll
; ModuleID = 'hello.c'
source_filename = "hello.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-redhat-linux"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
; Function Attrs: noinline nounwind optnone uwtable
define i32 @main(i32, i8**) #0 {
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i8**, align 8
%6 = alloca i32, align 4
store i32 0, i32* %3, align 4
store i32 %0, i32* %4, align 4
store i8** %1, i8*** %5, align 8
store i32 0, i32* %6, align 4
br label %7
; <label>:7: ; preds = %13, %2
%8 = load i32, i32* %6, align 4
%9 = icmp slt i32 %8, 10
br i1 %9, label %10, label %16
; <label>:10: ; preds = %7
%11 = load i32, i32* %6, align 4
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 %11)
br label %13
; <label>:13: ; preds = %10
%14 = load i32, i32* %6, align 4
%15 = add nsw i32 %14, 1
store i32 %15, i32* %6, align 4
br label %7
; <label>:16: ; preds = %7
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { noinline nounwind optnone uwtable
"correctly-rounded-divide-sqrt-fp-math"="false"
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-jump-tables"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"no-trapping-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
attributes #1 = {
"correctly-rounded-divide-sqrt-fp-math"="false"
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"no-trapping-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"Fedora clang version 6.0.0 (trunk 316308) (based on LLVM
6.0.0svn)"}
$ /opt/llvm-svn//bin/opt -S -mem2reg -loops -loop-simplify -loop-rotate
-lcssa -loop-unroll -sccp -simplifycfg hello3.ll -o hello3.loop.ll
$ cat hello3.loop.ll
; ModuleID = 'hello3.ll'
source_filename = "hello.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-redhat-linux"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
; Function Attrs: noinline nounwind optnone uwtable
define i32 @main(i32, i8**) #0 {
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i8**, align 8
%6 = alloca i32, align 4
store i32 0, i32* %3, align 4
store i32 %0, i32* %4, align 4
store i8** %1, i8*** %5, align 8
store i32 0, i32* %6, align 4
br label %7
; <label>:7: ; preds = %13, %2
%8 = load i32, i32* %6, align 4
%9 = icmp slt i32 %8, 10
br i1 %9, label %10, label %16
; <label>:10: ; preds = %7
%11 = load i32, i32* %6, align 4
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 %11)
br label %13
; <label>:13: ; preds = %10
%14 = load i32, i32* %6, align 4
%15 = add nsw i32 %14, 1
store i32 %15, i32* %6, align 4
br label %7
; <label>:16: ; preds = %7
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { noinline nounwind optnone uwtable
"correctly-rounded-divide-sqrt-fp-math"="false"
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-jump-tables"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"no-trapping-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
attributes #1 = {
"correctly-rounded-divide-sqrt-fp-math"="false"
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"no-trapping-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"Fedora clang version 6.0.0 (trunk 316308) (based on LLVM
6.0.0svn)"}
LLVM 6.0's LoopUnroll PASS failed to unroll loops?
But LLVM 3.9.1 is able to work:
$ clang --version
clang version 3.9.1 (tags/RELEASE_391/final)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
$ clang -S -emit-llvm hello.c -o hello1.ll
$ cat hello1.ll
; ModuleID = 'hello.c'
source_filename = "hello.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
; Function Attrs: nounwind uwtable
define i32 @main(i32, i8**) #0 {
%3 = alloca i32, align 4
%4 = alloca i32, align 4
%5 = alloca i8**, align 8
%6 = alloca i32, align 4
store i32 0, i32* %3, align 4
store i32 %0, i32* %4, align 4
store i8** %1, i8*** %5, align 8
store i32 0, i32* %6, align 4
br label %7
; <label>:7: ; preds = %13, %2
%8 = load i32, i32* %6, align 4
%9 = icmp slt i32 %8, 10
br i1 %9, label %10, label %16
; <label>:10: ; preds = %7
%11 = load i32, i32* %6, align 4
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 %11)
br label %13
; <label>:13: ; preds = %10
%14 = load i32, i32* %6, align 4
%15 = add nsw i32 %14, 1
store i32 %15, i32* %6, align 4
br label %7
; <label>:16: ; preds = %7
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { nounwind uwtable
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-jump-tables"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
attributes #1 = { "disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
!llvm.ident = !{!0}
!0 = !{!"clang version 3.9.1 (tags/RELEASE_391/final)"}
$ opt -S -mem2reg -loops -loop-simplify -loop-rotate -lcssa -loop-unroll
-sccp -simplifycfg hello1.ll -o hello1.loop.ll
$ cat hello1.loop.ll
; ModuleID = 'hello1.ll'
source_filename = "hello.c"
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
; Function Attrs: nounwind uwtable
define i32 @main(i32, i8**) #0 {
%3 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 0)
%4 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 1)
%5 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 2)
%6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 3)
%7 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 4)
%8 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 5)
%9 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 6)
%10 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 7)
%11 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 8)
%12 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 9)
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { nounwind uwtable
"disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-jump-tables"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
attributes #1 = { "disable-tail-calls"="false"
"less-precise-fpmad"="false"
"no-frame-pointer-elim"="true"
"no-frame-pointer-elim-non-leaf"
"no-infs-fp-math"="false"
"no-nans-fp-math"="false"
"no-signed-zeros-fp-math"="false"
"stack-protector-buffer-size"="8"
"target-cpu"="x86-64"
"target-features"="+fxsr,+mmx,+sse,+sse2,+x87"
"unsafe-fp-math"="false"
"use-soft-float"="false" }
!llvm.ident = !{!0}
!0 = !{!"clang version 3.9.1 (tags/RELEASE_391/final)"}
And also LLVM 3.1 is still able to work:
$ ./build/Release+Asserts/bin/opt --version
LLVM (http://llvm.org/):
LLVM version 3.1
Optimized build with assertions.
Built Oct 23 2017 (16:22:51).
Default target: x86_64-unknown-linux-gnu
Host CPU: corei7-avx
$ ./build/Release+Asserts/bin/clang -S -emit-llvm hello.c -o hello.ll
$ cat hello.ll
; ModuleID = 'hello.c'
target datalayout =
"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
define i32 @main(i32 %argc, i8** %argv) nounwind uwtable {
entry:
%retval = alloca i32, align 4
%argc.addr = alloca i32, align 4
%argv.addr = alloca i8**, align 8
%bits = alloca [4 x i32], align 16
%iter = alloca i32, align 4
store i32 0, i32* %retval
store i32 %argc, i32* %argc.addr, align 4
store i8** %argv, i8*** %argv.addr, align 8
store i32 0, i32* %iter, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32* %iter, align 4
%cmp = icmp slt i32 %0, 10
br i1 %cmp, label %for.body, label %for.end
for.body: ; preds = %for.cond
%1 = load i32* %iter, align 4
%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x
i8]* @.str, i32 0, i32 0), i32 %1)
br label %for.inc
for.inc: ; preds = %for.body
%2 = load i32* %iter, align 4
%inc = add nsw i32 %2, 1
store i32 %inc, i32* %iter, align 4
br label %for.cond
for.end: ; preds = %for.cond
ret i32 0
}
declare i32 @printf(i8*, ...)
$ ./build/Release+Asserts/bin/opt -S -mem2reg -loops -loop-simplify
-loop-rotate -lcssa -loop-unroll -sccp -simplifycfg hello.ll -o
hello.loop.ll
$ cat hello.loop.ll
; ModuleID = 'hello.ll'
target datalayout =
"e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
@.str = private unnamed_addr constant [4 x i8] c"%d\0A\00", align 1
define i32 @main(i32 %argc, i8** %argv) nounwind uwtable {
entry:
%call = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4 x
i8]* @.str, i32 0, i32 0), i32 0)
%call.1 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 1)
%call.2 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 2)
%call.3 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 3)
%call.4 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 4)
%call.5 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 5)
%call.6 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 6)
%call.7 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 7)
%call.8 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 8)
%call.9 = call i32 (i8*, ...)* @printf(i8* getelementptr inbounds ([4
x i8]* @.str, i32 0, i32 0), i32 9)
ret i32 0
}
declare i32 @printf(i8*, ...)
Succeeded unrolled Optimized build with assertions.
Maybe I wrongly use the LoopUnroll PASS? or please give me some hints,
thanks a lot!
--
Regards,
Leslie Zhai - https://reviews.llvm.org/p/xiangzhai/