Yoma 37 Krias Shema before Sunrise

Rabbeinu Tam holds that the correct time to recite Krias Shema is after sunrise and the וותיקין - the meticulous ones would recite it before sunrise incorrectly because they wanted to juxtapose geulah (the brochos after shema) with Tefillah, which they said immediately after sunrise. From Tosfos, it is not clear if they fulfilled the mitzva of krias shema in that time (בדיעבד), or would they have to recite krias shema afterwards. The משכנות יעקב says that they were יוצא. Rashi in Brochos does hold this way that one could fulfill his obligation of connecting geulah with Tefillah even though he did not fulfill the mitzva of krias shema. (See שמועת חיים for further discussion.)