test/CodeGen/delete-null-pointer-checks.c


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// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-linux-gnu -O2 -o - %s | FileCheck -check-prefix=NULL-POINTER-INVALID  %s
// RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-linux-gnu -O2 -o - %s -fno-delete-null-pointer-checks | FileCheck -check-prefix=NULL-POINTER-VALID  %s

// Test that clang does not remove the null pointer check with
// -fno-delete-null-pointer-checks.
int null_check(int *P) {
// NULL-POINTER-VALID: %[[TOBOOL:.*]] = icmp eq i32* %P, null
// NULL-POINTER-INVALID-NOT: icmp eq
// NULL-POINTER-VALID: %[[SEL:.*]] = select i1 %[[TOBOOL:.*]], i32* null, i32*
// NULL-POINTER-INVALID-NOT: select i1
// NULL-POINTER-VALID: load i32, i32* %[[SEL:.*]]
  int *Q = P;
  if (P) {
    Q = P + 2;
  }
  return *Q;
}

// NULL-POINTER-INVALID-NOT: attributes #0 = {{.*}} "null-pointer-is-valid"="true"
// NULL-POINTER-VALID: attributes #0 = {{.*}} "null-pointer-is-valid"="true"