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59 lines
1.6 KiB
Rust
59 lines
1.6 KiB
Rust
// EMIT_MIR_FOR_EACH_PANIC_STRATEGY
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// Check that DestinationPropagation does not propagate an assignment to a function argument
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// (doing so can break usages of the original argument value)
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//@ test-mir-pass: DestinationPropagation
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fn dummy(x: u8) -> u8 {
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x
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}
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// EMIT_MIR copy_propagation_arg.foo.DestinationPropagation.diff
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fn foo(mut x: u8) {
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// CHECK-LABEL: fn foo(
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// CHECK: debug x => [[x:_.*]];
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// CHECK: dummy(move [[x]])
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// CHECK: [[x]] = move {{_.*}};
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// calling `dummy` to make a use of `x` that copyprop cannot eliminate
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x = dummy(x); // this will assign a local to `x`
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}
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// EMIT_MIR copy_propagation_arg.bar.DestinationPropagation.diff
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fn bar(mut x: u8) {
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// CHECK-LABEL: fn bar(
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// CHECK: debug x => [[x:_.*]];
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// CHECK: dummy(move [[x]])
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// CHECK: [[x]] = const 5_u8;
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dummy(x);
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x = 5;
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}
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// EMIT_MIR copy_propagation_arg.baz.DestinationPropagation.diff
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fn baz(mut x: i32) -> i32 {
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// CHECK-LABEL: fn baz(
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// CHECK: debug x => [[x:_.*]];
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// CHECK-NOT: [[x]] =
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// self-assignment to a function argument should be eliminated
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x = x;
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x
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}
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// EMIT_MIR copy_propagation_arg.arg_src.DestinationPropagation.diff
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fn arg_src(mut x: i32) -> i32 {
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// CHECK-LABEL: fn arg_src(
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// CHECK: debug x => [[x:_.*]];
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// CHECK: debug y => [[y:_.*]];
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// CHECK: [[y]] = copy [[x]]
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// CHECK: [[x]] = const 123_i32;
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// CHECK-NOT: {{_.*}} = copy [[y]];
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let y = x;
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x = 123; // Don't propagate this assignment to `y`
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y
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}
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fn main() {
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// Make sure the function actually gets instantiated.
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foo(0);
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bar(0);
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baz(0);
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arg_src(0);
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}
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