[llvm-dev] LLVM v6.0 Internalize and GlobalDCE PASS can not work together?
Leslie Zhai via llvm-dev
llvm-dev at lists.llvm.org
Tue Oct 24 21:22:15 PDT 2017
Hi LLVM developers,
$ cat hello.c
#include <stdio.h>
void foo() {
}
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 -Xclang -disable-O0-optnone -S -emit-llvm
hello.c -o hello2.ll
$ cat hello2.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: noinline nounwind uwtable
define void @foo() #0 {
entry:
ret void
}
; Function Attrs: noinline nounwind uwtable
define i32 @main(i32 %argc, i8** %argv) #0 {
entry:
%retval = alloca i32, align 4
%argc.addr = alloca i32, align 4
%argv.addr = alloca i8**, align 8
%i = alloca i32, align 4
store i32 0, i32* %retval, align 4
store i32 %argc, i32* %argc.addr, align 4
store i8** %argv, i8*** %argv.addr, align 8
store i32 0, i32* %i, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32, i32* %i, 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, i32* %i, align 4
%call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 %1)
br label %for.inc
for.inc: ; preds = %for.body
%2 = load i32, i32* %i, align 4
%inc = add nsw i32 %2, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
for.end: ; preds = %for.cond
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { noinline nounwind 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 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
(git at github.com:llvm-mirror/llvm.git
d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
$ /opt/llvm-svn/bin/opt -S -internalize -globaldce hello2.ll -o
hello2.dce.ll
$ cat hello2.dce.ll
; ModuleID = 'hello2.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"
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
(git at github.com:llvm-mirror/llvm.git
d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
$ /opt/llvm-svn/bin/lli hello2.dce.ll
'main' function not found in module.
*No* more Alive Functions, so LLVM v6.0 Internalize and GlobalDCE PASS
failed to MarkLive Function together?
But LLVM 3.1 is able to work together:
$ ./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 hello0.ll
$ cat hello0.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 void @foo() nounwind uwtable {
entry:
ret void
}
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
%i = 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* %i, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32* %i, 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* %i, 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* %i, align 4
%inc = add nsw i32 %2, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
for.end: ; preds = %for.cond
ret i32 0
}
declare i32 @printf(i8*, ...)
$ ./build/Release+Asserts/bin/opt -S -internalize -globaldce hello0.ll
-o hello0.dce.ll
$ cat hello0.dce.ll
; ModuleID = 'hello0.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:
%retval = alloca i32, align 4
%argc.addr = alloca i32, align 4
%argv.addr = alloca i8**, align 8
%i = 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* %i, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32* %i, 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* %i, 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* %i, align 4
%inc = add nsw i32 %2, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
for.end: ; preds = %for.cond
ret i32 0
}
declare i32 @printf(i8*, ...)
Succeeded drop DeadFunction foo.
Maybe I wrongly use the Internalize and GlobalDCE PASS together? please
give me some hints, thanks a lot!
PS: LLVM 6.0 Internalize PASS is able to work, internal foo:
$ /opt/llvm-svn/bin/opt -S -internalize hello2.ll -o hello2.internal.ll
$ cat hello2.internal.ll
; ModuleID = 'hello2.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: noinline nounwind uwtable
define internal void @foo() #0 {
entry:
ret void
}
; Function Attrs: noinline nounwind uwtable
define internal i32 @main(i32 %argc, i8** %argv) #0 {
entry:
%retval = alloca i32, align 4
%argc.addr = alloca i32, align 4
%argv.addr = alloca i8**, align 8
%i = alloca i32, align 4
store i32 0, i32* %retval, align 4
store i32 %argc, i32* %argc.addr, align 4
store i8** %argv, i8*** %argv.addr, align 8
store i32 0, i32* %i, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32, i32* %i, 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, i32* %i, align 4
%call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x
i8], [4 x i8]* @.str, i32 0, i32 0), i32 %1)
br label %for.inc
for.inc: ; preds = %for.body
%2 = load i32, i32* %i, align 4
%inc = add nsw i32 %2, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
for.end: ; preds = %for.cond
ret i32 0
}
declare i32 @printf(i8*, ...) #1
attributes #0 = { noinline nounwind 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 = !{!"clang version 6.0.0 (git at github.com:llvm-mirror/clang.git
0aed123216ad4a38a9c2b16f1783895fd5cb1a04)
(git at github.com:llvm-mirror/llvm.git
d209b37aec1e392dabbf9b5324ea4a60c36fbc55)"}
--
Regards,
Leslie Zhai - https://reviews.llvm.org/p/xiangzhai/
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