9e0c06d708
Let Clang emit `dead_on_return` attribute on pointer arguments that are passed indirectly, namely, large aggregates that the ABI mandates be passed by value; thus, the parameter is destroyed within the callee. Writes to such arguments are not observable by the caller after the callee returns. This should desirably enable further MemCpyOpt/DSE optimizations. Previous discussion: https://discourse.llvm.org/t/rfc-add-dead-on-return-attribute/86871.
33 lines
2.7 KiB
C++
33 lines
2.7 KiB
C++
// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple aarch64-linux -o - | FileCheck %s --check-prefix=AARCH64-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple aarch64-linux -o - | FileCheck %s --check-prefix=AARCH64-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple x86_64-linux -o - | FileCheck %s --check-prefix=X86_64-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple x86_64-linux -o - | FileCheck %s --check-prefix=X86_64-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple ppc64-linux -o - | FileCheck %s --check-prefix=PPC64-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple ppc64-linux -o - | FileCheck %s --check-prefix=PPC64-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple armv7-apple-darwin9 -target-abi aapcs -o - | FileCheck %s --check-prefix=AAPCS-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple armv7-apple-darwin9 -target-abi aapcs -o - | FileCheck %s --check-prefix=AAPCS-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple s390x-linux -o - | FileCheck %s --check-prefix=SYSTEMZ-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple s390x-linux -o - | FileCheck %s --check-prefix=SYSTEMZ-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple i686-linux -o - | FileCheck %s --check-prefix=CHARPTR-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple i686-linux -o - | FileCheck %s --check-prefix=CHARPTR-CXX
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// RUN: %clang_cc1 -emit-llvm -std=c99 -x c %s -triple xcore -o - | FileCheck %s --check-prefix=VOIDPTR-C
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// RUN: %clang_cc1 -emit-llvm -std=c++17 -x c++ %s -triple xcore -o - | FileCheck %s --check-prefix=VOIDPTR-CXX
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#include <stdarg.h>
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// AARCH64-C: define {{.*}} @f(i32 noundef %n, ptr dead_on_return noundef %list)
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// AARCH64-CXX: define {{.*}} @_Z1fiSt9__va_list(i32 noundef %n, ptr dead_on_return noundef %list)
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// X86_64-C: define {{.*}} @f(i32 noundef %n, ptr noundef %list)
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// X86_64-CXX: define {{.*}} @_Z1fiP13__va_list_tag(i32 noundef %n, ptr noundef %list)
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// PPC64-C: define {{.*}} @f(i32 noundef signext %n, ptr noundef %list)
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// PPC64-CXX: define {{.*}} @_Z1fiPc(i32 noundef signext %n, ptr noundef %list)
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// AAPCS-C: define {{.*}} @f(i32 noundef %n, [1 x i32] %list.coerce)
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// AAPCS-CXX: define {{.*}} @_Z1fiSt9__va_list(i32 noundef %n, [1 x i32] %list.coerce)
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// SYSTEMZ-C: define {{.*}} @f(i32 noundef signext %n, ptr noundef %list)
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// SYSTEMZ-CXX: define {{.*}} @_Z1fiP13__va_list_tag(i32 noundef signext %n, ptr noundef %list)
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// CHARPTR-C: define {{.*}} @f(i32 noundef %n, ptr noundef %list)
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// CHARPTR-CXX: define {{.*}} @_Z1fiPc(i32 noundef %n, ptr noundef %list)
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// VOIDPTR-C: define {{.*}} @f(i32 noundef %n, ptr noundef %list)
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// VOIDPTR-CXX: define {{.*}} @_Z1fiPv(i32 noundef %n, ptr noundef %list)
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void f(int n, va_list list) {}
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