acb5ee2f84
The IR is a bit different (in particular wrt naming) if debug-assertions-std is enabled. Peculiarly, the issue goes away if overflow-check-std is also enabled, which is why CI did not catch this.
34 lines
1.3 KiB
Rust
34 lines
1.3 KiB
Rust
//@ compile-flags: -O -Zmerge-functions=disabled
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//@ needs-deterministic-layouts
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//@ min-llvm-version: 21
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//@ ignore-std-debug-assertions (causes different value naming)
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#![crate_type = "lib"]
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//! Check that a temporary intermediate allocations can eliminated and replaced
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//! with memcpy forwarding.
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//! This requires Vec code to be structured in a way that avoids phi nodes from the
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//! zero-capacity length flowing into the memcpy arguments.
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// CHECK-LABEL: @vec_append_with_temp_alloc
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// CHECK-SAME: ptr{{.*}}[[DST:%[a-z]+]]{{.*}}ptr{{.*}}[[SRC:%[a-z]+]]
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#[no_mangle]
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pub fn vec_append_with_temp_alloc(dst: &mut Vec<u8>, src: &[u8]) {
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// CHECK-NOT: call void @llvm.memcpy
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// CHECK: call void @llvm.memcpy.{{.*}}[[DST]].i{{.*}}[[SRC]]
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// CHECK-NOT: call void @llvm.memcpy
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let temp = src.to_vec();
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dst.extend(&temp);
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// CHECK: ret
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}
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// CHECK-LABEL: @string_append_with_temp_alloc
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// CHECK-SAME: ptr{{.*}}[[DST:%[a-z]+]]{{.*}}ptr{{.*}}[[SRC:%[a-z]+]]
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#[no_mangle]
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pub fn string_append_with_temp_alloc(dst: &mut String, src: &str) {
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// CHECK-NOT: call void @llvm.memcpy
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// CHECK: call void @llvm.memcpy.{{.*}}[[DST]].i{{.*}}[[SRC]]
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// CHECK-NOT: call void @llvm.memcpy
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let temp = src.to_string();
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dst.push_str(&temp);
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// CHECK: ret
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}
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