From 2023452aff7ad6dbd346b7c0e636b9d2ceb9d534 Mon Sep 17 00:00:00 2001
From: Brandt Bucher <brandt@python.org>
Date: Thu, 13 Jul 2023 17:37:52 -0700
Subject: [PATCH] Try just setting the implict shift as needed

---
 .github/workflows/jit.yml |  4 ++--
 Python/jit.c              | 37 +++++++++++++++++++++++++------------
 2 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/.github/workflows/jit.yml b/.github/workflows/jit.yml
index 51322410a06474..b665ce0097272a 100644
--- a/.github/workflows/jit.yml
+++ b/.github/workflows/jit.yml
@@ -21,9 +21,9 @@ jobs:
           - true
           # - false
         llvm:
-          # - 14
+          - 14
           # - 15
-          - 16
+          # - 16
         include:
           # - target: i686-pc-windows-msvc/msvc
           #   architecture: i686
diff --git a/Python/jit.c b/Python/jit.c
index f20dc85eda42ed..1c1c9781e4a536 100644
--- a/Python/jit.c
+++ b/Python/jit.c
@@ -67,29 +67,42 @@ patch_one(unsigned char *location, HoleKind kind, uint64_t value, uint64_t adden
             uint32_t instruction = *addr;
             assert(((instruction & 0x3B000000) == 0x39000000) ||
                    ((instruction & 0x11C00000) == 0x11000000));
-            if ((value + addend) & 0x7) {  // XXX: Remote debugging info.
-                printf("PATCH_ABS_12: possibly unaligned value %lu + %lu (at %p)\n", value, addend, location);
-            };
             value = (value + addend) & ((1 << 12) - 1);
             int implicit_shift = 0;
             if ((instruction & 0x3B000000) == 0x39000000) {
                 implicit_shift = ((instruction >> 30) & 0x3);
+                // XXX: We shouldn't have to rewrite these (we *should* be
+                // able to just assert the alignment), but something's up with
+                // aarch64 + ELF (at least with LLVM 14, I haven't tested 15
+                // and 16):
                 switch (implicit_shift) {
+                    case 3:
+                        if ((value & 0x7) == 0) {
+                            break;
+                        }
+                        implicit_shift = 2;
+                        instruction = (instruction & ~(0x3UL << 30)) | (implicit_shift << 30);
+                        // Fall through...
+                    case 2:
+                        if ((value & 0x3) == 0) {
+                            break;
+                        }
+                        implicit_shift = 1;
+                        instruction = (instruction & ~(0x3UL << 30)) | (implicit_shift << 30);
+                        // Fall through...
+                    case 1:
+                        if ((value & 0x1) == 0) {
+                            break;
+                        }
+                        implicit_shift = 0;
+                        instruction = (instruction & ~(0x3UL << 30)) | (implicit_shift << 30);
+                        // Fall through...
                     case 0:
                         if ((instruction & 0x04800000) == 0x04800000) {
                             implicit_shift = 4;
                             assert(((value & 0xF) == 0));
                         }
                         break;
-                    case 1:
-                        assert(((value & 0x1) == 0));
-                        break;
-                    case 2:
-                        assert(((value & 0x3) == 0));
-                        break;
-                    case 3:
-                        assert(((value & 0x7) == 0));
-                        break;
                 }
             }
             value >>= implicit_shift;