Prevent generating EEOP_AGG_STRICT_INPUT_CHECK operations when nargs == 0.

anarazel · anarazel · commit 793beab37e8f · 2018-11-03T15:55:23.000-07:00
This only became a problem with 4c640f4, which didn't synchronize the value agg_strict_input_check.nargs is set to, with the guard condition for emitting the operation. Besides such instructions being unnecessary overhead, currently the LLVM JIT provider doesn't support them. It seems more sensible to avoid generating such instruction than supporting them. Add assertions to make it easier to debug a potential further occurance. Discussion: https://postgr.es/m/2a505161-2727-2473-7c46-591ed108ac52@email.cz Backpatch: 11-, like 4c640f4.
diff --git a/src/backend/executor/execExpr.c b/src/backend/executor/execExpr.c
@@ -3023,7 +3023,7 @@ ExecBuildAggTrans(AggState *aggstate, AggStatePerPhase phase,
 		 * just keep the prior transValue. This is true for both plain and
 		 * sorted/distinct aggregates.
 		 */
-		if (trans_fcinfo->flinfo->fn_strict && numInputs > 0)
+		if (trans_fcinfo->flinfo->fn_strict && pertrans->numTransInputs > 0)
 		{
 			scratch.opcode = EEOP_AGG_STRICT_INPUT_CHECK;
 			scratch.d.agg_strict_input_check.nulls = strictnulls;
diff --git a/src/backend/jit/llvm/llvmjit_expr.c b/src/backend/jit/llvm/llvmjit_expr.c
@@ -2124,6 +2124,8 @@ llvm_compile_expr(ExprState *state)
 					LLVMValueRef v_nullp;
 					LLVMBasicBlockRef *b_checknulls;
 
+					Assert(nargs > 0);
+
 					jumpnull = op->d.agg_strict_input_check.jumpnull;
 					v_nullp = l_ptr_const(nulls, l_ptr(TypeStorageBool));
 

Original file line number	Diff line number	Diff line change
`@@ -3023,7 +3023,7 @@ ExecBuildAggTrans(AggState *aggstate, AggStatePerPhase phase,`
`3023`	`3023`	`* just keep the prior transValue. This is true for both plain and`
`3024`	`3024`	`* sorted/distinct aggregates.`
`3025`	`3025`	`*/`
`3026`		`- if (trans_fcinfo->flinfo->fn_strict && numInputs > 0)`
	`3026`	`+ if (trans_fcinfo->flinfo->fn_strict && pertrans->numTransInputs > 0)`
`3027`	`3027`	`{`
`3028`	`3028`	`scratch.opcode = EEOP_AGG_STRICT_INPUT_CHECK;`
`3029`	`3029`	`scratch.d.agg_strict_input_check.nulls = strictnulls;`