Rebased and addressed a couple of comments.

Rebased, and modified the logic to find the insertion point for the epilogue code.

Rebased.

Committed (ill formed commit message so phabricator did not pick it up)

Rebased prior to commit.

Rebased prior to commit.

In D62686#1571192, @asb wrote:

Hi Lewis, did you evaluate implementing the machine outliner as a more general approach for getting code size savings in this sort of way?

Abandoned since this is no longer relevant to RISC-V; other individual fixes for issues relating to this problem have been merged since. I will keep D61907 around for discussion even though it's a similar 'big hammer' approach to the problem.

In D62686#1571192, @asb wrote:

Hi Lewis, did you evaluate implementing the machine outliner as a more general approach for getting code size savings in this sort of way?

You should have tests for at least a subset of target-abi {ilp32,lp64}{f,d} and the compiler shouldn't assert in those cases.

Rebased and updated to use '0(' prefix for memory constraints.

Add support for a split save/restore approach when callee saved registers from the floating point ABIs are used.

Rebased

In D62686#1571360, @lewis-revill wrote:

Will do, I can rebase this patch on top of your hard float patch.

In D62686#1571192, @asb wrote:

Hi Lewis, did you evaluate implementing the machine outliner as a more general approach for getting code size savings in this sort of way?

I've reworked this patch to safely work around the implementation of save/restore via libcalls. These place constraints on the save/restore points that can be chosen by the shrink wrapping algorithm.

Rebase, and only use the getUseSaveRestoreLibCalls getter method rather than the useSaveRestoreLibCalls method which does not save its result.

Quick end-of-file newline fix

Added additional tests

Rebased to incorporate the recent CFI additions.

Just a quick comment, I'm assuming this depends on D58335 based on the test file you've modified?

Should the error change at all? We'll still get 'error: operand must be a bare symbol name' for call foo, bar. I guess this patch doesn't put us in a greate situation now that parseCallSymbol can return NoMatch even though technically we parsed a call symbol...

Abandoned in favour of D61907

Updated to address comments

Added nounwind to test functions.

Rebased and added testing using -relocation-model=pic in 'calls.ll'. Also added a dso_local callee to 'calls.ll' since this affects whether PLT is used for PIC.

Rebased patch after addition of matchRegisterNameHelper

Add Constraint_A to account for future modifications to Constraint_m handling. Constraint_A should only ever utilize a single base address without an offset.

• Rebased and fixed test run line

• Updated llc test check lines
• Add invalid constraint test
• Address use of auto

Revert previous change as the information needed to check the size cost was not available.

Added a basic check to avoid using save/restore libcalls if we know it will make the code size worse.

• Replaced split fixed/nonfixed vectors by simply interpreting the CSI vector differently depending if save/restore calls will be used or not.

I might need to go through the variable/function names to replace 'CSR' with CalleeSavedRegister or something that doesn't cause confusion with RISC-V 'CSR' meaning 'Control & Status Register'...