llvmGen: Fix #14251

Fixes the calling convention for functions passing raw SSE-register
values by adding padding as needed to get the values in the right
registers. This problem cropped up when some args were unused an dropped
from the live list.

This folds together 2e23e1c7 and
73273be4 previously from @kavon.

Metric Increase:
    T12707
    ManyConstructors
22 jobs for !2422 with wip/T14251 in 423 minutes and 19 seconds (queued for 2 seconds)
detached
Status Job ID Name Coverage
  Lint
passed #235143
lint
ghc-linters

00:00:15

passed #235144
lint
lint-linters

00:00:15

passed #235147
lint
lint-submods-mr

00:00:18

passed #235145
lint
lint-testsuite

00:00:17

passed #235146
lint
typecheck-testsuite

00:00:16

 
  Quick Build
passed #235148
x86_64-linux
hadrian-ghc-in-ghci

00:09:57

 
  Build
passed #235149
x86_64-linux
validate-x86_64-linux-deb9-hadrian

01:23:46

 
  Full Build
failed #235152
aarch64-linux allowed to fail
validate-aarch64-linux-deb9

03:45:37

passed #235153
armv7-linux
validate-armv7-linux-deb9

03:32:00

passed #235154
x86_64-linux
validate-i386-linux-deb9

01:35:38

passed #235151
x86_64-darwin
validate-x86_64-darwin

01:05:44

passed #235155
x86_64-linux
validate-x86_64-linux-deb9-debug

03:34:24

passed #235157
x86_64-linux
validate-x86_64-linux-deb9-dwarf

01:07:37

passed #235156
x86_64-linux
validate-x86_64-linux-deb9-integer-simple

01:37:12

passed #235150
x86_64-linux
validate-x86_64-linux-deb9-unreg-hadrian

02:18:16

passed #235158
x86_64-linux
validate-x86_64-linux-fedora27

01:39:17

passed #235160
x86_64-windows
validate-x86_64-windows

02:49:16

failed #235159
x86_64-windows allowed to fail
validate-x86_64-windows-hadrian

01:25:08

 
  Cleanup
passed #235161
x86_64-darwin
cleanup-darwin

00:00:15

 
  Packaging
passed #235162
x86_64-linux
doc-tarball

00:03:31

 
  Testing
manual #235163
x86_64-linux allowed to fail manual
hackage
passed #235164
x86_64-linux
perf-nofib

00:34:30

 
Name Stage Failure
failed
validate-x86_64-windows-hadrian Full Build
ghc.tar.xz: found 1 matching files                 
WARNING: junit.xml: no matching files
WARNING: Failed to load system CertPool:crypto/x509: system root pool is not available on Windows
Uploading artifacts to coordinator... ok
id=235159 responseStatus=201 Created token=kEp3Ptkn
Uploading artifacts...
Runtime platform
arch=amd64 os=windows pid=8012 revision=1f513601 version=11.10.1
WARNING: junit.xml: no matching files
ERROR: No files to upload
ERROR: Job failed: exit status 1
failed
validate-aarch64-linux-deb9 Full Build
Uploading artifacts...
ghc-aarch64-linux-deb9.tar.xz: found 1 matching files
junit.xml: found 1 matching files

performance-metrics.tsv: found 1 matching files

Uploading artifacts to coordinator... ok
id=235152 responseStatus=201 Created token=2AyDyeaz
Uploading artifacts...
junit.xml: found 1 matching files

Uploading artifacts to coordinator... ok
id=235152 responseStatus=201 Created token=2AyDyeaz
ERROR: Job failed: exit code 1