<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/62305>62305</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            clang-16.0.0 fatal error: error in backend: Cannot select
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          anbu1024
      </td>
    </tr>
</table>

<pre>
    ```
$ clang 1.c

fatal error: error in backend: Cannot select: 0x55ae0ee38910: i64 = bitcast 0x55ae0ee387c0
 0x55ae0ee387c0: i32,ch = load<(dereferenceable load (s32) from %ir.2)> 0x55ae0ee38750, FrameIndex:i64<0>, undef:i64
    0x55ae0ee384b0: i64 = FrameIndex<0>
    0x55ae0ee38590: i64 = undef
In function: foo
clang-16: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 16.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/bin
clang-16: note: diagnostic msg: 

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang-16: note: diagnostic msg: /tmp/1-348f26.c
clang-16: note: diagnostic msg: /tmp/1-348f26.sh
clang-16: note: diagnostic msg: 


---

$ cat /tmp/1-41ff31.c


# 1 "<built-in>"
# 1 "1.c"

void foo(int arg)
{
  int x = 0;
  
  unsigned char *y = __builtin_assume_aligned(arg, 16);
  
 for (int i = 0; i < 8; ++i)
    x = y[i];

 return;
}

---

$ cat /tmp/1-41ff31.sh

# Crash reproducer for clang version 16.0.0
# Driver args: "1.c"
# Original command:  "clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang-16" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-obj" "-mrelax-all" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "1.c" "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-mllvm" "-treat-scalable-fixed-error-as-warning" "-debugger-tuning=gdb" "-fcoverage-compilation-dir=/home/xxx/llvm-test" "-resource-dir" "clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/lib/clang/16" "-internal-isystem" "clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/lib/clang/16/include" "-internal-isystem" "/usr/local/include" "-internal-isystem" "/usr/lib/gcc/x86_64-linux-gnu/10/../../../../x86_64-linux-gnu/include" "-internal-externc-isystem" "/usr/include/x86_64-linux-gnu" "-internal-externc-isystem" "/include" "-internal-externc-isystem" "/usr/include" "-fdebug-compilation-dir=/home/xxx/llvm-test" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-o" "/tmp/1-eabb2d.o" "-x" "c" "1.c"
 "clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang-16" "-cc1" "-triple" "x86_64-unknown-linux-gnu" "-emit-obj" "-mrelax-all" "-disable-free" "-clear-ast-before-backend" "-disable-llvm-verifier" "-discard-value-names" "-main-file-name" "1.c" "-mrelocation-model" "pic" "-pic-level" "2" "-pic-is-pie" "-mframe-pointer=all" "-fmath-errno" "-ffp-contract=on" "-fno-rounding-math" "-mconstructor-aliases" "-funwind-tables=2" "-target-cpu" "x86-64" "-tune-cpu" "generic" "-mllvm" "-treat-scalable-fixed-error-as-warning" "-debugger-tuning=gdb" "-fcoverage-compilation-dir=/home/xxx/llvm-test" "-fdebug-compilation-dir=/home/xxx/llvm-test" "-ferror-limit" "19" "-fgnuc-version=4.2.1" "-fcolor-diagnostics" "-faddrsig" "-D__GCC_HAVE_DWARF2_CFI_ASM=1" "-x" "c" "1-41ff31.c"

---

$ clang --version
clang version 16.0.0
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /path-to/clang+llvm-16.0.0-x86_64-linux-gnu-ubuntu-18.04/bin

---

This is a regression bug, clang-14.0.6 is not affected.
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzsGEtv47j519AXgoJEyY8cfHCsaCbAtFnMpN2jQZGfZO5SpEFSjuffF6QedjIZdJsWPbQLGDL1vd-fJOacbDXAFi3v0bJcsN4fjd0yXfdZSotFbcT3LVql4y8tUbpDtMBcMd3iLOEjKF4b5pnCYK2xKN8NByw1rhn_HbQIsD3T2njsQAH3AZBelksGKUC-ucvSAJGrAqO8xLX0nDl_S7HmowlvgYEtp4ju-THyKsMEyveIbgRYaMCC5sBqBRGDEd24QH6HG2s6jOhS2iTco_zhlehliugeV5Z18KgFXFC-k6sC5fsU5Q8B1WsBzQgdLMP4VkJRv_LpVtIg4z2m5d0rpkFHJHzUuOk199LoQNEYM8BjOki2msMeDkOOGmu0By0wN13HtMANkwoEfpH-iOEiPeZGAF6nISq9A0zO2BvsALDUZ8NZVEbvbhThM1gnjcbZKkmTMSXPzLYQU3rZrA6rgvT6d21eNFFS9xfS6n6kO1pgAndGgArUJ-PkZfLOeaYUiFJeHUD0XqlzRwZdZBQ-CyV93Wvfk2yTpAWiVS31jyHRxkP4F5K12jgvOe5cGyC35fvLl4fdtwe8e37e7T_j588PuHr68uXp18e_fsLV45eHb_j5KYLv__YJf3345enrM8onXgsnazg4BwI701sOochCiYWYM-cMl8yDwLbX2HErT34msKEsecQyP4v8gw7QyncnRKuM5MWmoaupJT_K7o4fjd9wJYS8AoZhwfytoiJrmvzN6JiIc5xhRCnK93UvlSdSx0ajb_CBewbG69lIEfuBbqT2mNl2rlm0vp_aLKAusalSlM_Q6b_XcRgKzI_MYkR33yPp4RBtkfrAnOs7ODAVyRDdRDV7nK3i7HgrsDFBSrRHzkrjcY834YjoPaL3crY0zIHBvO9oeS_RspyFjgQWfG_1FbouPxT7KcnXsO4tc0ccq1j0HGw0_ufdHlhKK89gQ6jdUEqv00Jz_GRlKzVT0-wJZIHuo41Nq7kqKQ2CCOfZdPRWnhSMdz-dQSMxdNITU_823XcWFLsQptQEEdKFhUEaCzBrU8AsYc6TGhpjgUyb7Q1P9OsMVjYS7A2SMyvImakeiGYduFk7k5o0Ug3gEToEc7ZunMRkGJwD4iRnkpPkRMF5RtFbhHTkJGcvuiZsIXIyUnuwKC9vvG465o8ErNVmBjUnwo32loWNXYZlMCK0Idb0WkjdksA3K-BGO2977o0lTEnmrq42vX6RWhAfAuVQXs6G-rhACD_11xySVTGjew03yBY02Kv7XQj5tRKAeeI4U0MG5QUEiWuRMEdemNUylN-YFqj7tgUbFARwXrainq3l5gyWtUC46U5SDSkQYT2ViFZHE7JVXS4XRKuYdA_OT8wWhkUQ6QfYRwpfyXoq_NDCc-nH7GmmiHTfnYfuP6qikpqrXsA_UYZo1TsbJBjO1AfYouKW8xDFN0YGS1JEqyT58fIO7c80wyUc-M8smNnekflHJf27qsdai5X4kUJrhtpWspMTLLubka3uORlnOMrLIqFJdlPfylhy3evXPmVCWCfnNikPh0_7_eHz7u8Ph_LX3deKHvbV42H37S8oL2d55urjtHGA1TUVyTxOLlOdvhpz43r7czf8uRv-L3bD_0Kz_9DJ1yf718_m7z2WxidLMpv633-5RLQ6hXr25rr6Pvam-a6Tz0fpsHSYYQutBRddqvv4ujAOqiJJk1Wg0cZj1jTAPYhkFDJ9clmIbS7u8ju2gG222oRkbzbrxXHLxKrhkBU5W9NNXqxzzu-WmyxPac6bLIWF3NKU5mlB8zTPNuk6qZuMw6pZrzcsK2qRoyKFjkmVBK8TY9uFdK6H7Yrm6XKhWA3Kxe9ClGp4wREZMrssF3YbI1X3rUNFqqTz7irFS69gO03jEEv8r34ZWvRWbY_en8KbBaJVeEiQ_tjXCTfd2BVTc5ys-Q24Dws1WOgQraIH_wgAAP__pi6UHA">