diff --git a/src/intel/compiler/jay/jay_assign_accumulators.c b/src/intel/compiler/jay/jay_assign_accumulators.c
index e1b96170ac3..04f8a0eb214 100644
--- a/src/intel/compiler/jay/jay_assign_accumulators.c
+++ b/src/intel/compiler/jay/jay_assign_accumulators.c
@@ -323,11 +323,12 @@ pass(jay_function *func)
           *
           * The bspec says "Instructions that specify an implicit accumulator
           * source cannot specify an explicit accumulator source operand.". But
-          * it works fine on Lunar Lake so ¯\_(ツ)_/¯
+          * it works fine on Lunar Lake so ¯\_(ツ)_/¯ ... gate on !strict.
           */
          if ((I->op == JAY_OPCODE_MAD && I->type == JAY_TYPE_F32) &&
              (I->src[2].file == ACCUM && I->src[2].reg == 0) &&
-             !(I->src[2].negate || I->src[2].abs)) {
+             !(I->src[2].negate || I->src[2].abs) &&
+             !(jay_debug & JAY_DBG_STRICT)) {
 
             I->op = JAY_OPCODE_MAC;
          }
diff --git a/src/intel/compiler/jay/jay_from_nir.c b/src/intel/compiler/jay/jay_from_nir.c
index 8cf0651059b..ef0083eaddd 100644
--- a/src/intel/compiler/jay/jay_from_nir.c
+++ b/src/intel/compiler/jay/jay_from_nir.c
@@ -41,6 +41,7 @@ static const struct debug_named_value jay_debug_options[] = {
    { "sync",        JAY_DBG_SYNC,        "Sync after every instruction"          },
    { "noacc",       JAY_DBG_NOACC,       "Disable accumulator substitution"      },
    { "nosched",     JAY_DBG_NOSCHED,     "Disable scheduling"                    },
+   { "strict",      JAY_DBG_STRICT,      "Strictly conform to bspec/fulsim"      },
    DEBUG_NAMED_VALUE_END
 };
 
diff --git a/src/intel/compiler/jay/jay_private.h b/src/intel/compiler/jay/jay_private.h
index 1ce8638346e..29100310d88 100644
--- a/src/intel/compiler/jay/jay_private.h
+++ b/src/intel/compiler/jay/jay_private.h
@@ -18,6 +18,7 @@ extern "C" {
 #define JAY_DBG_SYNC        BITFIELD_BIT(3)
 #define JAY_DBG_NOACC       BITFIELD_BIT(4)
 #define JAY_DBG_NOSCHED     BITFIELD_BIT(5)
+#define JAY_DBG_STRICT      BITFIELD_BIT(6)
 extern int jay_debug;
 
 bool jay_nir_lower_bool(nir_shader *nir);