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stage2: LLVM backend: fix const packed structs

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When doing LLVM const bit shifting we must make sure the integer bit
sizes are wide enough or else LLVM gives us a poison result.
This commit is contained in:
Andrew Kelley
2021-12-27 16:59:26 -07:00
parent 3abe464b06
commit 886df772f0
5 changed files with 55 additions and 62 deletions
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10
src/codegen/llvm.zig
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@@ -1361,10 +1361,12 @@ pub const DeclGen = struct {
.val = field_val,
});
const ty_bit_size = @intCast(u16, field.ty.bitSize(target));
const llvm_int_ty = dg.context.intType(ty_bit_size);
const int_val = non_int_val.constBitCast(llvm_int_ty);
const shift_rhs = llvm_int_ty.constInt(running_bits, .False);
const shifted = int_val.constShl(shift_rhs);
const small_int_ty = dg.context.intType(ty_bit_size);
const small_int_val = non_int_val.constBitCast(small_int_ty);
const big_int_ty = running_int.typeOf();
const shift_rhs = big_int_ty.constInt(running_bits, .False);
const extended_int_val = small_int_val.constZExt(big_int_ty);
const shifted = extended_int_val.constShl(shift_rhs);
running_int = running_int.constOr(shifted);
running_bits += ty_bit_size;
} else {

5
src/codegen/llvm/bindings.zig
View File

@@ -201,6 +201,11 @@ pub const Value = opaque {
pub const addCase = LLVMAddCase;
extern fn LLVMAddCase(Switch: *const Value, OnVal: *const Value, Dest: *const BasicBlock) void;
pub inline fn isPoison(Val: *const Value) bool {
return LLVMIsPoison(Val).toBool();
}
extern fn LLVMIsPoison(Val: *const Value) Bool;
};
pub const Type = opaque {