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llvm-project/llvm/test/CodeGen/X86/arg-copy-elide.ll

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Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
; RUN: llc -mtriple=i686-windows < %s | FileCheck %s
X86ISelLowering: Only perform copy elision on legal types. This fixes cases where i1 types were not properly legalized yet and lead to the creating of 0-sized stack slots. This fixes http://llvm.org/PR32136 llvm-svn: 296950
2017-03-04 09:40:40 +08:00
declare void @addrof_i1(i1*)
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
declare void @addrof_i32(i32*)
declare void @addrof_i64(i64*)
declare void @addrof_i128(i128*)
declare void @addrof_i32_x3(i32*, i32*, i32*)
define void @simple(i32 %x) {
entry:
%x.addr = alloca i32
store i32 %x, i32* %x.addr
call void @addrof_i32(i32* %x.addr)
ret void
}
; CHECK-LABEL: _simple:
; CHECK: leal 4(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: retl
; We need to load %x before calling addrof_i32 now because it could mutate %x in
; place.
define i32 @use_arg(i32 %x) {
entry:
%x.addr = alloca i32
store i32 %x, i32* %x.addr
call void @addrof_i32(i32* %x.addr)
ret i32 %x
}
; CHECK-LABEL: _use_arg:
; CHECK: pushl %[[csr:[^ ]*]]
; CHECK-DAG: movl 8(%esp), %[[csr]]
; CHECK-DAG: leal 8(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: movl %[[csr]], %eax
; CHECK: popl %[[csr]]
; CHECK: retl
X86ISelLowering: Only perform copy elision on legal types. This fixes cases where i1 types were not properly legalized yet and lead to the creating of 0-sized stack slots. This fixes http://llvm.org/PR32136 llvm-svn: 296950
2017-03-04 09:40:40 +08:00
; We won't copy elide for types needing legalization such as i64 or i1.
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
define i64 @split_i64(i64 %x) {
entry:
%x.addr = alloca i64, align 4
store i64 %x, i64* %x.addr, align 4
call void @addrof_i64(i64* %x.addr)
ret i64 %x
}
; CHECK-LABEL: _split_i64:
; CHECK: pushl %ebp
; CHECK: movl %esp, %ebp
; CHECK: pushl %[[csr2:[^ ]*]]
; CHECK: pushl %[[csr1:[^ ]*]]
; CHECK: andl $-8, %esp
; CHECK-DAG: movl 8(%ebp), %[[csr1]]
; CHECK-DAG: movl 12(%ebp), %[[csr2]]
[X86] Fix arg copy elision for illegal types Use the store size of the argument type, which will be a byte-sized quantity, rather than dividing the size in bits by 8. Fixes PR32136 and re-enables copy elision from i64 arguments. Reverts the workaround in from r296950. llvm-svn: 297045
2017-03-07 02:39:39 +08:00
; CHECK-DAG: leal 8(%ebp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
; CHECK: calll _addrof_i64
; CHECK-DAG: movl %[[csr1]], %eax
; CHECK-DAG: movl %[[csr2]], %edx
; CHECK: leal -8(%ebp), %esp
; CHECK: popl %[[csr1]]
; CHECK: popl %[[csr2]]
; CHECK: popl %ebp
; CHECK: retl
X86ISelLowering: Only perform copy elision on legal types. This fixes cases where i1 types were not properly legalized yet and lead to the creating of 0-sized stack slots. This fixes http://llvm.org/PR32136 llvm-svn: 296950
2017-03-04 09:40:40 +08:00
define i1 @i1_arg(i1 %x) {
%x.addr = alloca i1
store i1 %x, i1* %x.addr
call void @addrof_i1(i1* %x.addr)
ret i1 %x
}
; CHECK-LABEL: _i1_arg:
; CHECK: pushl %ebx
; CHECK: movb 8(%esp), %bl
; CHECK: leal 8(%esp), %eax
; CHECK: pushl %eax
; CHECK: calll _addrof_i1
; CHECK: addl $4, %esp
; CHECK: movl %ebx, %eax
; CHECK: popl %ebx
; CHECK: retl
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
; We can't copy elide when an i64 is split between registers and memory in a
; fastcc function.
define fastcc i64 @fastcc_split_i64(i64* %p, i64 %x) {
entry:
%x.addr = alloca i64, align 4
store i64 %x, i64* %x.addr, align 4
call void @addrof_i64(i64* %x.addr)
ret i64 %x
}
; CHECK-LABEL: _fastcc_split_i64:
; CHECK: pushl %ebp
; CHECK: movl %esp, %ebp
; CHECK-DAG: movl %edx, %[[r1:[^ ]*]]
; CHECK-DAG: movl 8(%ebp), %[[r2:[^ ]*]]
; CHECK-DAG: movl %[[r2]], 4(%esp)
[MachineCopyPropagation] Extend pass to do COPY source forwarding Summary: This change extends MachineCopyPropagation to do COPY source forwarding and adds an additional run of the pass to the default pass pipeline just after register allocation. This version of this patch uses the newly added MachineOperand::isRenamable bit to avoid forwarding registers is such a way as to violate constraints that aren't captured in the Machine IR (e.g. ABI or ISA constraints). This change is a continuation of the work started in D30751. Reviewers: qcolombet, javed.absar, MatzeB, jonpa, tstellar Subscribers: tpr, mgorny, mcrosier, nhaehnle, nemanjai, jyknight, hfinkel, arsenm, inouehrs, eraman, sdardis, guyblank, fedor.sergeev, aheejin, dschuff, jfb, myatsina, llvm-commits Differential Revision: https://reviews.llvm.org/D41835 llvm-svn: 323991
2018-02-02 02:54:01 +08:00
; CHECK-DAG: movl %edx, (%esp)
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
; CHECK: movl %esp, %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i64
; CHECK: popl %ebp
; CHECK: retl
; We can't copy elide when it would reduce the user requested alignment.
define void @high_alignment(i32 %x) {
entry:
%x.p = alloca i32, align 128
store i32 %x, i32* %x.p
call void @addrof_i32(i32* %x.p)
ret void
}
; CHECK-LABEL: _high_alignment:
; CHECK: andl $-128, %esp
; CHECK: movl 8(%ebp), %[[reg:[^ ]*]]
; CHECK: movl %[[reg]], (%esp)
; CHECK: movl %esp, %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: retl
; We can't copy elide when it would reduce the ABI required alignment.
; FIXME: We should lower the ABI alignment of i64 on Windows, since MSVC
; doesn't guarantee it.
define void @abi_alignment(i64 %x) {
entry:
%x.p = alloca i64
store i64 %x, i64* %x.p
call void @addrof_i64(i64* %x.p)
ret void
}
; CHECK-LABEL: _abi_alignment:
; CHECK: andl $-8, %esp
; CHECK: movl 8(%ebp), %[[reg:[^ ]*]]
; CHECK: movl %[[reg]], (%esp)
; CHECK: movl %esp, %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i64
; CHECK: retl
; The code we generate for this is unimportant. This is mostly a crash test.
define void @split_i128(i128* %sret, i128 %x) {
entry:
%x.addr = alloca i128
store i128 %x, i128* %x.addr
call void @addrof_i128(i128* %x.addr)
store i128 %x, i128* %sret
ret void
}
; CHECK-LABEL: _split_i128:
; CHECK: pushl %ebp
; CHECK: calll _addrof_i128
; CHECK: retl
; Check that we load all of x, y, and z before the call.
define i32 @three_args(i32 %x, i32 %y, i32 %z) {
entry:
%z.addr = alloca i32, align 4
%y.addr = alloca i32, align 4
%x.addr = alloca i32, align 4
store i32 %z, i32* %z.addr, align 4
store i32 %y, i32* %y.addr, align 4
store i32 %x, i32* %x.addr, align 4
call void @addrof_i32_x3(i32* %x.addr, i32* %y.addr, i32* %z.addr)
%s1 = add i32 %x, %y
%sum = add i32 %s1, %z
ret i32 %sum
}
; CHECK-LABEL: _three_args:
; CHECK: pushl %[[csr:[^ ]*]]
; CHECK-DAG: movl {{[0-9]+}}(%esp), %[[csr]]
; CHECK-DAG: addl {{[0-9]+}}(%esp), %[[csr]]
; CHECK-DAG: addl {{[0-9]+}}(%esp), %[[csr]]
; CHECK-DAG: leal 8(%esp), %[[x:[^ ]*]]
; CHECK-DAG: leal 12(%esp), %[[y:[^ ]*]]
; CHECK-DAG: leal 16(%esp), %[[z:[^ ]*]]
; CHECK: pushl %[[z]]
; CHECK: pushl %[[y]]
; CHECK: pushl %[[x]]
; CHECK: calll _addrof_i32_x3
; CHECK: movl %[[csr]], %eax
; CHECK: popl %[[csr]]
; CHECK: retl
define void @two_args_same_alloca(i32 %x, i32 %y) {
entry:
%x.addr = alloca i32
store i32 %x, i32* %x.addr
store i32 %y, i32* %x.addr
call void @addrof_i32(i32* %x.addr)
ret void
}
; CHECK-LABEL: _two_args_same_alloca:
; CHECK: movl 8(%esp), {{.*}}
; CHECK: movl {{.*}}, 4(%esp)
; CHECK: leal 4(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: retl
define void @avoid_byval(i32* byval %x) {
entry:
%x.p.p = alloca i32*
store i32* %x, i32** %x.p.p
call void @addrof_i32(i32* %x)
ret void
}
; CHECK-LABEL: _avoid_byval:
; CHECK: leal {{[0-9]+}}(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: retl
define void @avoid_inalloca(i32* inalloca %x) {
entry:
%x.p.p = alloca i32*
store i32* %x, i32** %x.p.p
call void @addrof_i32(i32* %x)
ret void
}
; CHECK-LABEL: _avoid_inalloca:
; CHECK: leal {{[0-9]+}}(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: retl
; Don't elide the copy when the alloca is escaped with a store.
define void @escape_with_store(i32 %x) {
%x1 = alloca i32
%x2 = alloca i32*
store i32* %x1, i32** %x2
%x3 = load i32*, i32** %x2
store i32 0, i32* %x3
store i32 %x, i32* %x1
call void @addrof_i32(i32* %x1)
ret void
}
; CHECK-LABEL: _escape_with_store:
Elide stores which are overwritten without being observed. Summary: In SelectionDAG, when a store is immediately chained to another store to the same address, elide the first store as it has no observable effects. This is causes small improvements dealing with intrinsics lowered to stores. Test notes: * Many testcases overwrite store addresses multiple times and needed minor changes, mainly making stores volatile to prevent the optimization from optimizing the test away. * Many X86 test cases optimized out instructions associated with associated with va_start. * Note that test_splat in CodeGen/AArch64/misched-stp.ll no longer has dependencies to check and can probably be removed and potentially replaced with another test. Reviewers: rnk, john.brawn Subscribers: aemerson, rengolin, qcolombet, jyknight, nemanjai, nhaehnle, javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D33206 llvm-svn: 303198
2017-05-17 03:43:56 +08:00
; CHECK: movl {{.*}}(%esp), %[[reg:[^ ]*]]
; CHECK: movl %[[reg]], [[offs:[0-9]*]](%esp)
Elide argument copies during instruction selection Summary: Avoids tons of prologue boilerplate when arguments are passed in memory and left in memory. This can happen in a debug build or in a release build when an argument alloca is escaped. This will dramatically affect the code size of x86 debug builds, because X86 fast isel doesn't handle arguments passed in memory at all. It only handles the x86_64 case of up to 6 basic register parameters. This is implemented by analyzing the entry block before ISel to identify copy elision candidates. A copy elision candidate is an argument that is used to fully initialize an alloca before any other possibly escaping uses of that alloca. If an argument is a copy elision candidate, we set a flag on the InputArg. If the the target generates loads from a fixed stack object that matches the size and alignment requirements of the alloca, the SelectionDAG builder will delete the stack object created for the alloca and replace it with the fixed stack object. The load is left behind to satisfy any remaining uses of the argument value. The store is now dead and is therefore elided. The fixed stack object is also marked as mutable, as it may now be modified by the user, and it would be invalid to rematerialize the initial load from it. Supersedes D28388 Fixes PR26328 Reviewers: chandlerc, MatzeB, qcolombet, inglorion, hans Subscribers: igorb, llvm-commits Differential Revision: https://reviews.llvm.org/D29668 llvm-svn: 296683
2017-03-02 05:42:00 +08:00
; CHECK: calll _addrof_i32
; This test case exposed issues with the use of TokenFactor.
define void @sret_and_elide(i32* sret %sret, i32 %v) {
%v.p = alloca i32
store i32 %v, i32* %v.p
call void @addrof_i32(i32* %v.p)
store i32 %v, i32* %sret
ret void
}
; CHECK-LABEL: _sret_and_elide:
; CHECK: pushl
; CHECK: pushl
; CHECK: movl 12(%esp), %[[sret:[^ ]*]]
; CHECK: movl 16(%esp), %[[v:[^ ]*]]
; CHECK: leal 16(%esp), %[[reg:[^ ]*]]
; CHECK: pushl %[[reg]]
; CHECK: calll _addrof_i32
; CHECK: movl %[[v]], (%[[sret]])
; CHECK: movl %[[sret]], %eax
; CHECK: popl
; CHECK: popl
; CHECK: retl