migrate make_ptr_const to new anonymous decl mechanism

Instead of creating Module.Decl objects, directly create InternPool
pointer values using the anon_decl Addr encoding.

The LLVM backend needed code to notice the alignment of the pointer and
lower accordingly. The other backends likely need a similar change.

src/Sema.zig

@@ -3657,9 +3657,10 @@ fn zirMakePtrConst(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileErro
     const elem_ty = ptr_info.child.toType();
 
     if (try sema.resolveComptimeKnownAllocValue(block, alloc, null)) |val| {
-        var anon_decl = try block.startAnonDecl();
+        const new_mut_ptr = Air.internedToRef((try mod.intern(.{ .ptr = .{
-        defer anon_decl.deinit();
+            .ty = alloc_ty.toIntern(),
-        const new_mut_ptr = try sema.analyzeDeclRef(try anon_decl.finish(elem_ty, val.toValue(), ptr_info.flags.alignment));
+            .addr = .{ .anon_decl = val },
+        } })));
         return sema.makePtrConst(block, new_mut_ptr);
     }
 

src/codegen/llvm.zig

@@ -3049,6 +3049,7 @@ pub const Object = struct {
         o: *Object,
         decl_val: InternPool.Index,
         llvm_addr_space: Builder.AddrSpace,
+        alignment: InternPool.Alignment,
     ) Error!Builder.Variable.Index {
         // TODO: Add address space to the anon_decl_map
         const gop = try o.anon_decl_map.getOrPut(o.gpa, decl_val);
@@ -3068,6 +3069,8 @@ pub const Object = struct {
         try variable_index.setInitializer(try o.lowerValue(decl_val), &o.builder);
         variable_index.setLinkage(.internal, &o.builder);
         variable_index.setUnnamedAddr(.unnamed_addr, &o.builder);
+        if (alignment != .none)
+            variable_index.setAlignment(alignment.toLlvm(), &o.builder);
         return variable_index;
     }
 
@@ -4415,7 +4418,8 @@ pub const Object = struct {
 
         const addr_space = target_util.defaultAddressSpace(target, .global_constant);
         const llvm_addr_space = toLlvmAddressSpace(addr_space, target);
-        const llvm_global = (try o.resolveGlobalAnonDecl(decl_val, llvm_addr_space)).ptrConst(&o.builder).global;
+        const alignment = ptr_ty.ptrAlignment(mod);
+        const llvm_global = (try o.resolveGlobalAnonDecl(decl_val, llvm_addr_space, alignment)).ptrConst(&o.builder).global;
 
         const llvm_val = try o.builder.convConst(
             .unneeded,

test/behavior.zig

@@ -37,7 +37,6 @@ test {
     _ = @import("behavior/bugs/1500.zig");
     _ = @import("behavior/bugs/1607.zig");
     _ = @import("behavior/bugs/1735.zig");
-    _ = @import("behavior/bugs/1741.zig");
     _ = @import("behavior/bugs/1851.zig");
     _ = @import("behavior/bugs/1914.zig");
     _ = @import("behavior/bugs/2006.zig");

test/behavior/align.zig

@@ -15,6 +15,15 @@ test "global variable alignment" {
     }
 }
 
+test "large alignment of local constant" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
+    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
+
+    const x: f32 align(128) = 12.34;
+    try std.testing.expect(@intFromPtr(&x) % 128 == 0);
+}
+
 test "slicing array of length 1 can not assume runtime index is always zero" {
     if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
     if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO

test/behavior/bugs/1741.zig

@@ -1,11 +0,0 @@
-const std = @import("std");
-const builtin = @import("builtin");
-
-test "fixed" {
-    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
-    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
-    if (builtin.zig_backend == .stage2_spirv64) return error.SkipZigTest; // flaky
-
-    const x: f32 align(128) = 12.34;
-    try std.testing.expect(@intFromPtr(&x) % 128 == 0);
-}