[Bug 1837522] [NEW] GCC Miscompilation of vector shift

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Vector shift miscompilation
 
---Steps to Reproduce---
   t.c:
__vector int
foo (__vector int a, int s)
{
  return a << (s + 3);
}

gcc -O3 -march=z13 t.c -S -mzvector

foo:
        veslf   %v24,%v24,0(%r2)   <---- +3 is omitted
        br      %r14
 
Contact Information = andreas.krebbel at de.ibm.com 
 
Userspace tool common name: GCC 
 
The userspace tool has the following bit modes: 64 

Backported fix has been applied to GCC 8 branch as r273493:

https://gcc.gnu.org/viewcvs?rev=273493&root=gcc&view=rev

S/390: Fix vector shift count operand

We currently use subst definitions to handle the different variants of shift
count operands. Unfortunately, in the vector shift pattern the shift count
operand is used directly. Without it being adjusted for the 'subst' variants the
displacement value is omitted resulting in a wrong shift count being applied.

This patch needs to be applied to older branches as well.

gcc/ChangeLog:

2019-07-15  Andreas Krebbel  <krebbel at linux.ibm.com>

Backport from mainline
2019-07-01  Andreas Krebbel  <krebbel at linux.ibm.com>

* config/s390/vector.md: Fix shift count operand printing.

gcc/testsuite/ChangeLog:

2019-07-15  Andreas Krebbel  <krebbel at linux.ibm.com>

Backport from mainline
2019-07-01  Andreas Krebbel  <krebbel at linux.ibm.com>

* gcc.target/s390/vector/vec-shift-2.c: New test.

Added:
branches/gcc-8-branch/gcc/testsuite/gcc.target/s390/vector/vec-shift-2.c
Modified:
branches/gcc-8-branch/gcc/ChangeLog
branches/gcc-8-branch/gcc/config/s390/vector.md
branches/gcc-8-branch/gcc/testsuite/ChangeLog

** Affects: gcc-8 (Ubuntu)
     Importance: Undecided
     Assignee: Skipper Bug Screeners (skipper-screen-team)
         Status: New


** Tags: architecture-s39064 bugnameltc-179280 severity-high targetmilestone-inin---
-- 
GCC Miscompilation of vector shift
https://bugs.launchpad.net/bugs/1837522
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