If a variable has an initializer, codegen tries to build its value. If
the variable is large in size, building its value requires substantial
resources. It causes strange behavior from user viewpoint: compilation
of huge zero initialized arrays like:
char data_1[2147483648u] = { 0 };
consumes enormous amount of time and memory.
With this change codegen tries to determine if variable initializer is
equivalent to zero initializer. In this case variable value is not
constructed.
This change fixes PR18978.
Differential Revision: https://reviews.llvm.org/D46241
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@332847 91177308-0d34-0410-b5e6-96231b3b80d8
trailing fields may not be represented in initializer lists, they
are being handled as padding and those fields *must* be zero
initialized.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@101067 91177308-0d34-0410-b5e6-96231b3b80d8
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@91446 91177308-0d34-0410-b5e6-96231b3b80d8
Richard Smith