[clang] Skip auto-init on scalar vars that have a non-constant Init and no self-ref #94642
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@@ -18,7 +18,7 @@ typedef struct { | |
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| int foo(unsigned n) { | ||
| // scalar variable | ||
| long a; | ||
| // array | ||
| S arr[ARRLEN]; | ||
| // VLA | ||
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,121 @@ | ||
| // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -emit-llvm -o - | FileCheck %s -check-prefix=UNINIT | ||
| // RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=pattern %s -emit-llvm -o - | FileCheck %s -check-prefix=PATTERN | ||
| // RUN: %clang_cc1 -triple x86_64-unknown-unknown -ftrivial-auto-var-init=zero %s -emit-llvm -o - | FileCheck %s -check-prefix=ZERO | ||
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| template<typename T> void used(T &) noexcept; | ||
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| extern "C" { | ||
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| extern int get_int(int) noexcept; | ||
| struct C { | ||
| int x; | ||
| int y; | ||
| }; | ||
| extern C make_c() noexcept; | ||
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| // Scalar with a self-reference: does need auto-init. | ||
| // UNINIT-LABEL: test_selfinit_call( | ||
| // ZERO-LABEL: test_selfinit_call( | ||
| // ZERO: store i32 0, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_selfinit_call( | ||
| // PATTERN: store i32 -1431655766, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| void test_selfinit_call() { | ||
| int self = get_int(self); | ||
| used(self); | ||
| } | ||
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| // Scalar without a self-reference: no auto-init needed. | ||
| // UNINIT-LABEL: test_nonself_call( | ||
| // ZERO-LABEL: test_nonself_call( | ||
| // ZERO-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_nonself_call( | ||
| // PATTERN-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| void test_nonself_call() { | ||
| int x = get_int(2); | ||
| used(x); | ||
| } | ||
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| // Scalar with a self-reference: does need auto-init. | ||
| // UNINIT-LABEL: test_selfinit_lambda_call( | ||
| // ZERO-LABEL: test_selfinit_lambda_call( | ||
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There was a problem hiding this comment. Nit, if "UNINIT-LABEL", "ZERO-LABEL", and "PATTERN-LABEL" are always the same, just define a common label like "CHECK-LABEL:" to avoid redundancy? There was a problem hiding this comment. I'm not sure if a common "CHECK-LABEL:" would have the same semantics and help split the stream for matching when there is a different prefix like "ZERO: " (or "PATTERN:") that follows, or if the CHECK and the ZERO end up as a independent scans. If it's an independent scan, then "CHECK-LABEL" wouldn't have the same semantics as "ZERO-LABEL:" (which helps split the stream for the "ZERO:" checks that follow -- e.g., in case there a multiple places that could match something generic like "store i32 0, ", the preceding ZERO-LABEL help disambiguate which to match). I'd prefer to keep the redundancy just to be safe and more clear that the X-LABEL are for the X that it's associated with, unless you're pretty sure it can cross over different check prefixes. |
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| // ZERO: store i32 0, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_selfinit_lambda_call( | ||
| // PATTERN: store i32 -1431655766, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| void test_selfinit_lambda_call() { | ||
| int self = [&](){ return self; }(); | ||
| used(self); | ||
| } | ||
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| // Scalar with a self-reference: does need auto-init. | ||
| // UNINIT-LABEL: test_selfinit_gnu_stmt_expression( | ||
| // ZERO-LABEL: test_selfinit_gnu_stmt_expression( | ||
| // ZERO: store i32 0, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_selfinit_gnu_stmt_expression( | ||
| // PATTERN: store i32 -1431655766, ptr %self, align 4, !annotation [[AUTO_INIT:!.+]] | ||
| void test_selfinit_gnu_stmt_expression() { | ||
| int self = ({int x = self; x + 1; }); | ||
| used(self); | ||
| } | ||
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| // Not a scalar: auto-init just in case | ||
| // UNINIT-LABEL: test_nonscalar_call( | ||
| // ZERO-LABEL: test_nonscalar_call( | ||
| // ZERO: call void @llvm.memset{{.*}}, i8 0, i64 8, {{.*}} !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_nonscalar_call( | ||
| // PATTERN: call void @llvm.memcpy{{.*}}, i64 8, {{.*}} !annotation [[AUTO_INIT:!.+]] | ||
| void test_nonscalar_call() { | ||
| C c = make_c(); | ||
| used(c); | ||
| } | ||
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| // Scalar with a self-reference: does need auto-init. | ||
| // UNINIT-LABEL: test_self_ptr( | ||
| // ZERO-LABEL: test_self_ptr( | ||
| // ZERO: store ptr null, ptr %self, align 8, !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_self_ptr( | ||
| // PATTERN: store ptr inttoptr (i64 -6148914691236517206 to ptr), ptr %self, align 8, !annotation [[AUTO_INIT:!.+]] | ||
| void test_self_ptr() { | ||
| void* self = self; | ||
| used(self); | ||
| } | ||
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| // Scalar without a self-reference: no auto-init needed. | ||
| // UNINIT-LABEL: test_nonself_ptr( | ||
| // ZERO-LABEL: test_nonself_ptr( | ||
| // ZERO-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_nonself_ptr( | ||
| // PATTERN-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| void test_nonself_ptr() { | ||
| int y = 0; | ||
| void* x = &y; | ||
| used(x); | ||
| } | ||
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| // Scalar with a self-reference: does need auto-init. | ||
| // UNINIT-LABEL: test_self_complex( | ||
| // ZERO-LABEL: test_self_complex( | ||
| // ZERO: call void @llvm.memset{{.*}} !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_self_complex( | ||
| // PATTERN: call void @llvm.memcpy{{.*}} !annotation [[AUTO_INIT:!.+]] | ||
| void test_self_complex() { | ||
| _Complex float self = 3.0 * 3.0 * self; | ||
| used(self); | ||
| } | ||
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| // Scalar without a self-reference: no auto-init needed. | ||
| // UNINIT-LABEL: test_nonself_complex( | ||
| // ZERO-LABEL: test_nonself_complex( | ||
| // ZERO-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| // PATTERN-LABEL: test_nonself_complex( | ||
| // PATTERN-NOT: !annotation [[AUTO_INIT:!.+]] | ||
| void test_nonself_complex() { | ||
| _Complex float y = 0.0; | ||
| _Complex float x = 3.0 * 3.0 * y; | ||
| used(x); | ||
| } | ||
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| } // extern "C" | ||
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| // ZERO: [[AUTO_INIT]] = !{!"auto-init"} | ||
| // PATTERN: [[AUTO_INIT]] = !{!"auto-init"} | ||
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Can we have both the test cases in which scalar variables are auto-inited and where the initialization is skipped?
Something along the lines of:
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Sure! Added those cases.
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LGTM