Change Details

This patch allows iterating over PHI uses of an alloca when determining whether an alloca is only ever modified by a copy from global constant. Since PHI does not modify the memory allocated by the alloca instruction in question, we can safely add the incoming values of the PHI to the worklist for replacement and furthermore, the PHI itself as well. Define a new PHI as a copy of the old PHI except with its operands replaced according the WorkMap.

This patch adds on to the functionality implemented in rG42ab5dc5a5dd6c79476104bdc921afa2a18559cf, where PHI nodes are supported in the use-def traversal algorithm to determine if an alloca ever overwritten in addition to a memmove/memcpy. This patch implements the support needed by the PointerReplacer to collect all (indirect) users of the alloca in the case where a PHI is involved. Finally, a new PHI is defined in the replace method which takes in replaced incoming values and updates the WorkMap accordingly.

This patch allows iterating over PHI uses of an alloca whendds on to the functionality implemented determining whether an alloca is only ever modified by ain rG42ab5dc5a5dd6c79476104bdc921afa2a18559cf, copy from global constant. Since PHI does not modify thewhere PHI nodes are supported in the use-def traversal memory allocated by thealgorithm to determine if an alloca instruction in question,ever overwritten we can safely add the incoming values of the PHI to thein addition to a memmove/memcpy. This patch implements worklist for replacement and furthermore, the PHI itselfthe support needed by the PointerReplacer to collect as well. Define a new PHI as a copy ofall (indirect) users of the alloca in the old PHI exceptcase where a PHI with its operands replaced according the WorkMapis involved. Finally, a new PHI is defined in the replace method which takes in replaced incoming values and updates the WorkMap accordingly.