5.7 Restrictions on Using the Post-Link Optimizer

The following restrictions affect post-link optimization:

• The advice_only mode is the only post-link optimization support provided for FPU and VCU targets.
• Branches or calls to unlabeled destinations invalidate DP load optimizations. All branch destinations must have labels.
• If the position of the data sections depends on the size of the code sections, the data page layout information used to decide which DP load instructions to remove may no longer be valid.

For example, consider the following link command file:

SECTIONS { .text > MEM, .mydata > MEM,}

A change in the size of the .text section after optimizing causes the .mydata section to shift. Ensuring that all output data sections are aligned on a 64-word boundary removes this shifting issue. For example, consider the following link command file:

SECTIONS { .text > MEM, .mydata align = 64 > MEM,}