[DOC][GlobalIsel] Add description for G_FREEZE

[sunshaoce]

Description based on https://llvm.org/docs/LangRef.html#id333

[llvmbot]

@llvm/pr-subscribers-llvm-globalisel

Author: Shaoce SUN (sunshaoce)

Changes

Description based on https://llvm.org/docs/LangRef.html#id333

---

Full diff: https://github.com/llvm/llvm-project/pull/156707.diff

1 Files Affected:

• (modified) llvm/docs/GlobalISel/GenericOpcode.rst (+9)

diff --git a/llvm/docs/GlobalISel/GenericOpcode.rst b/llvm/docs/GlobalISel/GenericOpcode.rst
index eefd76de9c33a..b055327466739 100644
--- a/llvm/docs/GlobalISel/GenericOpcode.rst
+++ b/llvm/docs/GlobalISel/GenericOpcode.rst
@@ -1150,6 +1150,15 @@ An alignment value of `0` or `1` means no specific alignment.
 
   %8:_(p0) = G_DYN_STACKALLOC %7(s64), 32
 
+G_FREEZE
+^^^^^^^^
+
+G_FREEZE is used to stop propagation of undef and poison values.
+
+.. code-block:: none
+
+  %1:_(s32) = G_FREEZE %0(s32)
+
 Optimization Hints
 ------------------