From 3359d0323a3115601b49ac7d6860c8b15babb491 Mon Sep 17 00:00:00 2001 From: gingerBill Date: Tue, 30 Mar 2021 20:38:04 +0100 Subject: Change `>>` behaviour in LLVM to prevent stupid UB --- src/llvm_backend.cpp | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/llvm_backend.cpp') diff --git a/src/llvm_backend.cpp b/src/llvm_backend.cpp index 92b180f73..e8028eece 100644 --- a/src/llvm_backend.cpp +++ b/src/llvm_backend.cpp @@ -6600,7 +6600,6 @@ handle_op: LLVMValueRef bits = rhs.value; LLVMValueRef bit_size = LLVMConstInt(lb_type(p->module, rhs.type), 8*type_size_of(lhs.type), false); - LLVMValueRef max = LLVMConstInt(lb_type(p->module, rhs.type), 8*type_size_of(lhs.type)-1, false); LLVMValueRef width_test = LLVMBuildICmp(p->builder, LLVMIntULT, bits, bit_size, ""); @@ -6617,16 +6616,17 @@ handle_op: bool is_unsigned = is_type_unsigned(type); LLVMValueRef bit_size = LLVMConstInt(lb_type(p->module, rhs.type), 8*type_size_of(lhs.type), false); - LLVMValueRef max = LLVMConstInt(lb_type(p->module, rhs.type), 8*type_size_of(lhs.type)-1, false); LLVMValueRef width_test = LLVMBuildICmp(p->builder, LLVMIntULT, bits, bit_size, ""); - bits = LLVMBuildSelect(p->builder, width_test, bits, max, ""); if (is_unsigned) { - res.value = LLVMBuildLShr(p->builder, lhs.value, bits, ""); + res.value = LLVMBuildLShr(p->builder, lhsval, bits, ""); } else { res.value = LLVMBuildAShr(p->builder, lhsval, bits, ""); } + + LLVMValueRef zero = LLVMConstNull(lb_type(p->module, lhs.type)); + res.value = LLVMBuildSelect(p->builder, width_test, res.value, zero, ""); return res; } case Token_AndNot: -- cgit v1.2.3