mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-25 04:02:41 +01:00
a83e090ac2
In r339636 the alias analysis rules were changed with regards to tail calls
and byval arguments. Previously, tail calls were assumed not to alias
allocas from the current frame. This has been updated, to not assume this
for arguments with the byval attribute.
This patch aligns TailCallElim with the new rule. Tail marking can now be
more aggressive and mark more calls as tails, e.g.:
define void @test() {
%f = alloca %struct.foo
call void @bar(%struct.foo* byval %f)
ret void
}
define void @test2(%struct.foo* byval %f) {
call void @bar(%struct.foo* byval %f)
ret void
}
define void @test3(%struct.foo* byval %f) {
%agg.tmp = alloca %struct.foo
%0 = bitcast %struct.foo* %agg.tmp to i8*
%1 = bitcast %struct.foo* %f to i8*
call void @llvm.memcpy.p0i8.p0i8.i64(i8* %0, i8* %1, i64 40, i1 false)
call void @bar(%struct.foo* byval %agg.tmp)
ret void
}
The problematic case where a byval parameter is captured by a call is still
handled correctly, and will not be marked as a tail (see PR7272).
llvm-svn: 343986
76 lines
2.1 KiB
LLVM
76 lines
2.1 KiB
LLVM
; RUN: opt < %s -basicaa -tailcallelim -inline -instcombine -dse -S | FileCheck %s
|
|
; RUN: opt < %s -aa-pipeline=basic-aa -passes='function(tailcallelim),cgscc(inline,function(instcombine,dse))' -S | FileCheck %s
|
|
; PR7272
|
|
|
|
; Calls that capture byval parameters cannot be marked as tail calls. Other
|
|
; tails that don't capture byval parameters can still be tail calls.
|
|
|
|
target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32-n8:16:32"
|
|
target triple = "i386-pc-linux-gnu"
|
|
|
|
declare void @ext(i32*)
|
|
|
|
define void @bar(i32* byval %x) {
|
|
call void @ext(i32* %x)
|
|
ret void
|
|
}
|
|
|
|
define void @foo(i32* %x) {
|
|
; CHECK-LABEL: define void @foo(
|
|
; CHECK: llvm.lifetime.start
|
|
; CHECK: store i32 %2, i32* %x
|
|
call void @bar(i32* byval %x)
|
|
ret void
|
|
}
|
|
|
|
define internal void @qux(i32* byval %x) {
|
|
call void @ext(i32* %x)
|
|
tail call void @ext(i32* null)
|
|
ret void
|
|
}
|
|
|
|
define void @frob(i32* %x) {
|
|
; CHECK-LABEL: define void @frob(
|
|
; CHECK: %[[POS:.*]] = alloca i32
|
|
; CHECK: %[[VAL:.*]] = load i32, i32* %x
|
|
; CHECK: store i32 %[[VAL]], i32* %[[POS]]
|
|
; CHECK: {{^ *}}call void @ext(i32* nonnull %[[POS]]
|
|
; CHECK: tail call void @ext(i32* null)
|
|
; CHECK: ret void
|
|
tail call void @qux(i32* byval %x)
|
|
ret void
|
|
}
|
|
|
|
; A byval parameter passed into a function which is passed out as byval does
|
|
; not block the call from being marked as tail.
|
|
|
|
declare void @ext2(i32* byval)
|
|
|
|
define void @bar2(i32* byval %x) {
|
|
call void @ext2(i32* byval %x)
|
|
ret void
|
|
}
|
|
|
|
define void @foobar(i32* %x) {
|
|
; CHECK-LABEL: define void @foobar(
|
|
; CHECK: %[[POS:.*]] = alloca i32
|
|
; CHECK: %[[VAL:.*]] = load i32, i32* %x
|
|
; CHECK: store i32 %[[VAL]], i32* %[[POS]]
|
|
; CHECK: tail call void @ext2(i32* byval nonnull %[[POS]]
|
|
; CHECK: ret void
|
|
tail call void @bar2(i32* byval %x)
|
|
ret void
|
|
}
|
|
|
|
define void @barfoo() {
|
|
; CHECK-LABEL: define void @barfoo(
|
|
; CHECK: %[[POS:.*]] = alloca i32
|
|
; CHECK: %[[VAL:.*]] = load i32, i32* %x
|
|
; CHECK: store i32 %[[VAL]], i32* %[[POS]]
|
|
; CHECK: tail call void @ext2(i32* byval nonnull %[[POS]]
|
|
; CHECK: ret void
|
|
%x = alloca i32
|
|
tail call void @bar2(i32* byval %x)
|
|
ret void
|
|
}
|