Squashed commit of the following:

commit c05d7df4f9c90984d2c04126772be3fee1d81fd1
Author: Cliff Click <cliffc@acm.org>
Date:   Thu Aug 20 10:52:58 2026 -0700

    Fix local frefs, deferred inlining, and sys FileIO support

    - Defer non-trivial inlining out of CallEnd idealization and run it from IterPeeps after normal peepholes reach a fixed point.
    - Keep forward refs local to their lexical scope, promote them outward on scope pop, and track created FRefNodes directly for dependency  discovery.
    - Preserve loop scope shape when frefs are first seen inside loop bodies.
    - Treat frefs as final constants from creation and force lazy self lookups before implicit calls.
    - Reset imported pointer/struct types conservatively for post-parse Iter.
    - Pin Start-owned global machine value chains and clone global constants per function during GCM.
    - Improve late ASM printing before encoding and namespace constant-pool symbols.
    - Add optional regalloc function-local edge verifier and improve empty-mask splitting for multi-def/fixed-register LRGs.
    - Add sys array compare, safer array copy bounds, libc open/creat/close/unlink bindings, aryu8.str0, and higher-level sys.io file operations.
    - Add docs/examples/FileIO.smp and a Chapter25 FileIO test.
    - Update spill/code-size goldens after the allocator and scheduling changes.

commit ef5316979732ac118612d310b75923c8f59ecdc1
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 16:29:56 2026 -0700

    Dijkstra uses bitset.

    TestC.exec for repeated test runs with different stdins.
    Support &= and |= op-update forms.

commit 728a527587f19bb49860f02ae5ac5968ab01ae33
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 12:13:28 2026 -0700

    Fix live demo

commit e4c069b9ef2cbfafe28d8edfcbff55396cde085e
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 09:52:24 2026 -0700

    Update Dijkstra.smp

commit b8015739b4056e3f7a715a030e846a441021a9f1
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 09:41:17 2026 -0700

    Better looking Dijkstra

commit 7cce587804c6169b24829e0b5bdc10be94357a31
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 09:33:33 2026 -0700

    Fix CmpMemX86 encoding

    Use sys.aryu8 for number printing

commit 310b5d8c9978a3b09622a4b89dac97f0e5e6f3fb
Author: Cliff Click <cliffc@acm.org>
Date:   Fri Aug 14 09:04:58 2026 -0700

    Progress dijlstra

    Fix NotX86 encoding.  Allow Not-sinking through Phis; the Nots both take Scalar and might take different types (ptr vs int).  Better guard installing during && || opers.
    Drop the csv parse flavor in sys lib.

commit 5917d5322521dd5e762c4698d34e5d7ac9b3a37f
Author: Cliff Click <cliffc@acm.org>
Date:   Thu Aug 13 14:44:12 2026 -0700

    missed

commit da35ad4d8a330559a21c04ae6326536e0fd62c48
Author: Cliff Click <cliffc@acm.org>
Date:   Thu Aug 13 14:43:42 2026 -0700

    Major cleanup of allocation

    All the graph-gen is moved to the <ctor> declaration and not at the alloc site.

commit c4223216099ccbc526d282bb263972532d48c5b2
Author: Cliff Click <cliffc@acm.org>
Date:   Thu Aug 13 13:26:01 2026 -0700

    Some work from Dykstra (more coming)

commit a03bc567f61dc7e4355e453ee4be16ac2528d1ab
Author: Cliff Click <cliffc@acm.org>
Date:   Thu Aug 13 09:32:55 2026 -0700

    Spill correctness and improvements

    Had the callee-save pick-risky backwards vs cloneables.

commit 2d306e4430225f916cb7fb999f4926e52f6fb70a
Author: Cliff Click <cliffc@acm.org>
Date:   Wed Aug 12 19:40:04 2026 -0700

    Tighter parser handling of missing fields

    Bug fix add libc.errno, read can return -1, sys.ary exists

commit b7eeefda4cafa1e86153170dca6f13d45ef63f69
Author: Cliff Click <cliffc@acm.org>
Date:   Wed Aug 12 16:22:48 2026 -0700

    Printer improvements

commit 8b9112226f1d2d1c843b080eecefe0d5ddc1f8cf
Author: Cliff Click <cliffc@acm.org>
Date:   Wed Aug 12 15:30:46 2026 -0700

    Remove GLB

commit ae566f5c610b9c30831906d3f024901d8930a227
Author: Cliff Click <cliffc@acm.org>
Date:   Wed Aug 12 14:38:51 2026 -0700

    Add Capitalize example

    Rename Ary to ary.
    Fix bug || carrying state along.
    Fix bug load-array removing control.
    Add sys.char tolower/upper

1 files changed, 49 insertions, 16 deletions

diff --git a/chapter25/src/main/smp/sys/io.smp b/chapter25/src/main/smp/sys/io.smp
index b94e89fa..3d6be512 100644
--- a/chapter25/src/main/smp/sys/io.smp
+++ b/chapter25/src/main/smp/sys/io.smp
@@ -3,30 +3,63 @@
 // Simple I/O Library
 
 // Write byte array to stdout
-val p = { u8[~] str ->
-    i64 ptr = str;  // cast array base to i64
-    return libc.write(1,ptr,str#);
-};
-
-val p_noInline = { u8[~] str ->
-    i64 ptr = str;  // cast array base to i64
-    return libc.write(1,ptr,str#);
-};
+val p          = { u8[~] str -> write(1,str); };
+val p_noInline = { u8[~] str -> write(1,str); };
 
-// Return stdin as a u8[].
-val stdin = { ->
+// Return fd contents as a u8[].
+val read = { i32 fd ->
     var buf = new u8[8*1024];
     i64 ptr = buf;
     int len = 0;
     while( true ) {
-        int rez = libc.read(0,ptr,buf#);
-        if( rez < 0 ) libc._exit(libc.errno);
+        i32 rez = libc.read(fd,ptr,buf#);
+        if( rez > buf# ) libc._exit(libc.errno);
         len += rez;
         if( rez < buf# )
             break;
         libc._exit(-2); // Need to implement for more than 8K input
     }
-    // Compress
-    var dst = new u8[len];
-    return Ary.copy(dst,0,buf,0,len);
+    var out = new u8[len];
+    ary.copy(out,0,buf,0,len);
+};
+
+// Write all of str to fd.
+val write = { i32 fd, u8[~] str ->
+  i64 ptr = str;                // Convert array pointer to a i64 for the native call
+  libc.write(fd,ptr,str#);
+};
+
+// Write all of str to fd.
+val writeOff = { i32 fd, u8[~] str, u32 off, u32 len ->
+  i64 ptr = str;                // Convert array pointer to a i64 for the native call
+  ptr += off;                   // Skip offset
+  // Cap at available length
+  if( len > str# - off ) len = str# - off;
+  // Do the write
+  libc.write(fd,ptr,len);
+};
+
+// Return stdin as a u8[].
+val stdin = { -> read(0); };
+
+// Create file for writing.  Return fd, or -1 and errno has the error code
+val create = { u8[~] str ->
+    i64 ptr = sys.aryu8.str0(str);
+    i32 perms = 6*64 + 6*8 + 6; // 0666
+    return libc.creat(ptr, perms);
+};
+
+// Open file for reading.  Return fd, or -1 and errno has the error code
+val open = { u8[~] str ->
+    i64 ptr = sys.aryu8.str0(str);
+    return libc.open(ptr, sys.libc.O_RDONLY, 0);
+};
+
+// Close an open fd.  Return 0, or -1 and errno has the error code
+val close = { i32 fd -> return libc.close(fd); };
+
+// Remove a file.  Return 0, or -1 and errno has the error code
+val remove = { u8[~] str ->
+    i64 ptr = sys.aryu8.str0(str);
+    return libc.unlink(ptr);
 };