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commit    b8ecfbe5af4f1ccb7be582fe43b6568a7e8dd02b
Author:   David Rowley <drowley@postgresql.org>
Date:     Thu Oct 23 00:13:44 2025 +0000

    Fix incorrect zero extension of Datum in JIT tuple deform code
    
    When JIT deformed tuples (controlled via the jit_tuple_deforming GUC),
    types narrower than sizeof(Datum) would be zero-extended up to Datum
    width.  This wasn't the same as what fetch_att() does in the standard
    tuple deforming code.  Logically the values are the same when fetching
    via the DatumGet*() marcos, but negative numbers are not the same in
    binary form.
    
    In the report, the problem was manifesting itself with:
    
    ERROR: could not find memoization table entry
    
    in a query which had a "Cache Mode: binary" Memoize node. However, it's
    currently unclear what else is affected.  Anything that uses
    datum_image_eq() or datum_image_hash() on a Datum from a tuple deformed by
    JIT could be affected, but it may not be limited to that.
    
    The fix for this is simple: use signed extension instead of zero
    extension.
    
    Many thanks to Emmanuel Touzery for reporting this issue and providing
    steps and backup which allowed the problem to easily be recreated.
    
    Reported-by: Emmanuel Touzery <emmanuel.touzery@plandela.si>
    Author: David Rowley <dgrowleyml@gmail.com>
    Discussion: https://postgr.es/m/DB8P194MB08532256D5BAF894F241C06393F3A@DB8P194MB0853.EURP194.PROD.OUTLOOK.COM
    Backpatch-through: 13


 src/backend/jit/llvm/llvmjit_deform.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/backend/jit/llvm/llvmjit_deform.c b/src/backend/jit/llvm/llvmjit_deform.c
index 489ef34ec4c..a1bd08b40fc 100644
--- a/src/backend/jit/llvm/llvmjit_deform.c
+++ b/src/backend/jit/llvm/llvmjit_deform.c
@@ -677,7 +677,7 @@ slot_compile_deform(LLVMJitContext *context, TupleDesc desc,
 			v_tmp_loaddata =
 				LLVMBuildPointerCast(b, v_attdatap, vartypep, "");
 			v_tmp_loaddata = l_load(b, vartype, v_tmp_loaddata, "attr_byval");
-			v_tmp_loaddata = LLVMBuildZExt(b, v_tmp_loaddata, TypeSizeT, "");
+			v_tmp_loaddata = LLVMBuildSExt(b, v_tmp_loaddata, TypeSizeT, "");
 
 			LLVMBuildStore(b, v_tmp_loaddata, v_resultp);
 		}


[parent: caf529aba22d]