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auto merge of #17875 : dotdash/rust/static_bool, r=alexcrichton

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While booleans are represented as i1 in SSA values, LLVM expects them
to be stored/loaded as i8 values. Using i1 as we do now works, but
kills some optimizations, so we should switch to i8, just like we do
everywhere else.

Fixes #16959.
This commit is contained in:
bors 2014-10-09 12:47:01 +00:00
commit dfd52817ee
2 changed files with 15 additions and 2 deletions
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10
src/librustc/middle/trans/base.rs
View file

@ -2680,12 +2680,18 @@ pub fn get_item_val(ccx: &CrateContext, id: ast::NodeId) -> ValueRef {
// We need the translated value here, because for enums the
// LLVM type is not fully determined by the Rust type.
let (v, inlineable, _) = consts::const_expr(ccx, &**expr, is_local);
let (v, inlineable, ty) = consts::const_expr(ccx, &**expr, is_local);
ccx.const_values().borrow_mut().insert(id, v);
let mut inlineable = inlineable;
unsafe {
let llty = llvm::LLVMTypeOf(v);
// boolean SSA values are i1, but they have to be stored in i8 slots,
// otherwise some LLVM optimization passes don't work as expected
let llty = if ty::type_is_bool(ty) {
llvm::LLVMInt8TypeInContext(ccx.llcx())
} else {
llvm::LLVMTypeOf(v)
};
if contains_null(sym.as_slice()) {
ccx.sess().fatal(
format!("Illegal null byte in export_name value: `{}`",

7
src/librustc/middle/trans/consts.rs
View file

@ -701,6 +701,13 @@ pub fn trans_const(ccx: &CrateContext, m: ast::Mutability, id: ast::NodeId) {
// At this point, get_item_val has already translated the
// constant's initializer to determine its LLVM type.
let v = ccx.const_values().borrow().get_copy(&id);
// boolean SSA values are i1, but they have to be stored in i8 slots,
// otherwise some LLVM optimization passes don't work as expected
let v = if llvm::LLVMTypeOf(v) == Type::i1(ccx).to_ref() {
llvm::LLVMConstZExt(v, Type::i8(ccx).to_ref())
} else {
v
};
llvm::LLVMSetInitializer(g, v);
// `get_item_val` left `g` with external linkage, but we just set an