zig

commit 47f7ed1c4cb8acf7fed99a057fb84202962e4b1b (tree)
parent 6926e6e705b7d1c0a69ec20b6b0e1ea280f036d1
Author: Andrew Kelley <andrew@ziglang.org>
Date:   Thu, 19 Aug 2021 17:09:55 -0700

Revert "Add mask before truncating dereferenced bit pointers (#9584)"

This was a workaround for an LLVM 12 bug which has been fixed in LLVM
13.

This reverts commit 5cd1d42a351aa77d2a030e59cbd2b9abf7c44444 but keeps
the test case.

Diffstat:
M
src/stage1/codegen.cpp
 | 
13
+++++--------

1 file changed, 5 insertions(+), 8 deletions(-)
diff --git a/src/stage1/codegen.cpp b/src/stage1/codegen.cpp
@@ -3831,14 +3831,10 @@ static LLVMValueRef ir_render_load_ptr(CodeGen *g, Stage1Air *executable,
     LLVMValueRef shift_amt_val = LLVMConstInt(LLVMTypeOf(containing_int), shift_amt, false);
     LLVMValueRef shifted_value = LLVMBuildLShr(g->builder, containing_int, shift_amt_val, "");
 
-    LLVMTypeRef same_size_int = LLVMIntType(size_in_bits);
-    LLVMValueRef mask = LLVMConstAllOnes(LLVMIntType(size_in_bits));
-    mask = LLVMConstZExt(mask, LLVMTypeOf(containing_int));
-    LLVMValueRef masked_value = LLVMBuildAnd(g->builder, shifted_value, mask, "");
-
     if (handle_is_ptr(g, child_type)) {
         LLVMValueRef result_loc = ir_llvm_value(g, instruction->result_loc);
-        LLVMValueRef truncated_int = LLVMBuildTrunc(g->builder, masked_value, same_size_int, "");
+        LLVMTypeRef same_size_int = LLVMIntType(size_in_bits);
+        LLVMValueRef truncated_int = LLVMBuildTrunc(g->builder, shifted_value, same_size_int, "");
         LLVMValueRef bitcasted_ptr = LLVMBuildBitCast(g->builder, result_loc,
                                                       LLVMPointerType(same_size_int, 0), "");
         LLVMBuildStore(g->builder, truncated_int, bitcasted_ptr);
@@ -3846,11 +3842,12 @@ static LLVMValueRef ir_render_load_ptr(CodeGen *g, Stage1Air *executable,
     }
 
     if (child_type->id == ZigTypeIdFloat) {
-        LLVMValueRef truncated_int = LLVMBuildTrunc(g->builder, masked_value, same_size_int, "");
+        LLVMTypeRef same_size_int = LLVMIntType(size_in_bits);
+        LLVMValueRef truncated_int = LLVMBuildTrunc(g->builder, shifted_value, same_size_int, "");
         return LLVMBuildBitCast(g->builder, truncated_int, get_llvm_type(g, child_type), "");
     }
 
-    return LLVMBuildTrunc(g->builder, masked_value, get_llvm_type(g, child_type), "");
+    return LLVMBuildTrunc(g->builder, shifted_value, get_llvm_type(g, child_type), "");
 }
 
 static bool value_is_all_undef_array(CodeGen *g, ZigValue *const_val, size_t len) {