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158d72d728
Set the writable and dead_on_unwind attributes for sret arguments. These indicate that the argument points to writable memory (and it's legal to introduce spurious writes to it on entry to the function) and that the argument memory will not be used if the call unwinds. This enables additional MemCpyOpt/DSE/LICM optimizations.
24 lines
695 B
C
24 lines
695 B
C
// RUN: %clang_cc1 %s -Wno-strict-prototypes -emit-llvm -o - | FileCheck %s
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struct abc {
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long a;
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long b;
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long c;
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long d;
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long e;
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};
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struct abc foo1(void);
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// CHECK-DAG: declare {{.*}} @foo1(ptr dead_on_unwind writable sret(%struct.abc)
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struct abc foo2();
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// CHECK-DAG: declare {{.*}} @foo2(ptr dead_on_unwind writable sret(%struct.abc)
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struct abc foo3(void){}
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// CHECK-DAG: define {{.*}} @foo3(ptr dead_on_unwind noalias writable sret(%struct.abc)
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void bar(void) {
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struct abc dummy1 = foo1();
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// CHECK-DAG: call {{.*}} @foo1(ptr dead_on_unwind writable sret(%struct.abc)
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struct abc dummy2 = foo2();
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// CHECK-DAG: call {{.*}} @foo2(ptr dead_on_unwind writable sret(%struct.abc)
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}
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