[PATCH 2/3] target/arm: Make IT insn undef when not present

The IT insn is introduced for A-profile starting in v6T2; for
M-profile it is present when the Main Extension is implemented (which
includes v7M and excludes v6M).  We were missing the feature-check,
so fail to UNDEF on earlier cores.

Add the missing check.

Cc: [email protected]
Fixes: 9ee6e8bb853bde ("ARMv7 support.")
Signed-off-by: Peter Maydell <[email protected]>
---
 target/arm/tcg/translate.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/target/arm/tcg/translate.c b/target/arm/tcg/translate.c
index df98dc2e34d..103e2fe7c73 100644
--- a/target/arm/tcg/translate.c
+++ b/target/arm/tcg/translate.c
@@ -6038,6 +6038,16 @@ static bool trans_IT(DisasContext *s, arg_IT *a)
 {
     int cond_mask = a->cond_mask;
 
+    /*
+     * IT insn introduced in v6T2 for A-profile; it is only present
+     * on M-profile if the Main Extension is implemented.
+     */
+    if (!arm_dc_feature(s, ARM_FEATURE_THUMB2) ||
+        (arm_dc_feature(s, ARM_FEATURE_M) &&
+         !arm_dc_feature(s, ARM_FEATURE_M_MAIN))) {
+        return false;
+    }
+
     /*
      * No actual code generated for this insn, just setup state.
      *
-- 
2.43.0