b5376ba601
I added this back in 111999, but I no longer think it's a good idea - It had to get scaled back to only power-of-two things to not break a bunch of targets - LLVM seems to be getting better at memcpy removal anyway - Introducing vector instructions has seemed to sometimes (115515) make autovectorization worse So this removes it from the codegen crates entirely, and instead just tries to use <https://doc.rust-lang.org/nightly/nightly-rustc/rustc_codegen_ssa/traits/builder/trait.BuilderMethods.html#method.typed_place_copy> instead of direct `memcpy` so things will still use load/store for immediates.
52 lines
1.8 KiB
Rust
52 lines
1.8 KiB
Rust
//@ compile-flags: -O -C no-prepopulate-passes
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//@ only-x86_64 (to not worry about usize differing)
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//@ ignore-debug: precondition checks make mem::replace not a candidate for MIR inlining
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#![crate_type = "lib"]
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#[no_mangle]
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// CHECK-LABEL: @replace_usize(
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pub fn replace_usize(r: &mut usize, v: usize) -> usize {
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// CHECK-NOT: alloca
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// CHECK: %[[R:.+]] = load i64, ptr %r
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// CHECK: store i64 %v, ptr %r
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// CHECK: ret i64 %[[R]]
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std::mem::replace(r, v)
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}
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#[no_mangle]
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// CHECK-LABEL: @replace_ref_str(
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pub fn replace_ref_str<'a>(r: &mut &'a str, v: &'a str) -> &'a str {
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// CHECK-NOT: alloca
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// CHECK: %[[A:.+]] = load ptr
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// CHECK: %[[B:.+]] = load i64
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// CHECK-NOT: store
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// CHECK-NOT: load
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// CHECK: store ptr
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// CHECK: store i64
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// CHECK-NOT: load
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// CHECK-NOT: store
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// CHECK: %[[P1:.+]] = insertvalue { ptr, i64 } poison, ptr %[[A]], 0
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// CHECK: %[[P2:.+]] = insertvalue { ptr, i64 } %[[P1]], i64 %[[B]], 1
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// CHECK: ret { ptr, i64 } %[[P2]]
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std::mem::replace(r, v)
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}
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#[no_mangle]
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// CHECK-LABEL: @replace_short_array_3(
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pub fn replace_short_array_3(r: &mut [u32; 3], v: [u32; 3]) -> [u32; 3] {
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// CHECK-NOT: alloca
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// CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %result, ptr align 4 %r, i64 12, i1 false)
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// CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %r, ptr align 4 %v, i64 12, i1 false)
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std::mem::replace(r, v)
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}
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#[no_mangle]
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// CHECK-LABEL: @replace_short_array_4(
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pub fn replace_short_array_4(r: &mut [u32; 4], v: [u32; 4]) -> [u32; 4] {
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// CHECK-NOT: alloca
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// CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %result, ptr align 4 %r, i64 16, i1 false)
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// CHECK: call void @llvm.memcpy.p0.p0.i64(ptr align 4 %r, ptr align 4 %v, i64 16, i1 false)
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std::mem::replace(r, v)
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}
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