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

   1 // RUN: %clang_cc1 -emit-llvm -triple x86_64-unknown-linux-gnu -O2 -o - %s | FileCheck -check-prefix=NULL-POINTER-INVALID  %s
   2 // 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
   3
   4 // Test that clang does not remove the null pointer check with
   5 // -fno-delete-null-pointer-checks.
   6 int null_check(int *P) {
   7 // NULL-POINTER-VALID: %[[TOBOOL:.*]] = icmp eq ptr %P, null
   8 // NULL-POINTER-INVALID-NOT: icmp eq
   9 // NULL-POINTER-VALID: %[[SEL:.*]] = select i1 %[[TOBOOL:.*]], ptr null, ptr
  10 // NULL-POINTER-INVALID-NOT: select i1
  11 // NULL-POINTER-VALID: load i32, ptr %[[SEL:.*]]
  12   int *Q = P;
  13   if (P) {
  14     Q = P + 2;
  15   }
  16   return *Q;
  17 }
  18
  19 // NULL-POINTER-INVALID-NOT: attributes #0 = {{.*}} null_pointer_is_valid
  20 // NULL-POINTER-VALID: attributes #0 = {{.*}} null_pointer_is_valid