[X86] Use getAllOnesConstant instead of getConstant(-1). NFC

[topperc]

A while back I had tried to clean up cases where getConstant was implicitly truncating constants. Initially by manual audit and later with an assert. I only committed patches from the assert testing.

This code path isn't executed in lit tests so I only found it with the manual audit. This patch was still sitting in my stash so thought I go ahead and post it.

[llvmbot]

@llvm/pr-subscribers-backend-x86

Author: Craig Topper (topperc)

Changes

A while back I had tried to clean up cases where getConstant was implicitly truncating constants. Initially by manual audit and later with an assert. I only committed patches from the assert testing.

This code path isn't executed in lit tests so I only found it with the manual audit. This patch was still sitting in my stash so thought I go ahead and post it.

---

Full diff: https://github.com/llvm/llvm-project/pull/114299.diff

1 Files Affected:

• (modified) llvm/lib/Target/X86/X86ISelLowering.cpp (+1-1)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 34bc5d76c15cea..22cba69af41f51 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -49321,7 +49321,7 @@ static SDValue combineVectorShiftImm(SDNode *N, SelectionDAG &DAG,
   if (!LogicalShift && ISD::isBuildVectorAllOnes(N0.getNode()))
     // N0 is all ones or undef. We guarantee that the bits shifted into the
     // result are all ones, not undef.
-    return DAG.getConstant(-1, SDLoc(N), VT);
+    return DAG.getAllOnesConstant(SDLoc(N), VT);
 
   auto MergeShifts = [&](SDValue X, uint64_t Amt0, uint64_t Amt1) {
     unsigned NewShiftVal = Amt0 + Amt1;

[RKSimon]

LGTM

[llvm-ci]

LLVM Buildbot has detected a new failure on builder openmp-offload-libc-amdgpu-runtime running on omp-vega20-1 while building llvm at step 10 "Add check check-offload".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/73/builds/7794

Here is the relevant piece of the build log for the reference

Step 10 (Add check check-offload) failure: 1200 seconds without output running [b'ninja', b'-j 32', b'check-offload'], attempting to kill
...
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug50022.cpp (866 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug53727.cpp (867 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug47654.cpp (868 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/test_libc.cpp (869 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/wtime.c (870 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu :: offloading/std_complex_arithmetic.cpp (871 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu :: offloading/bug49021.cpp (872 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/complex_reduction.cpp (873 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/bug49021.cpp (874 of 879)
PASS: libomptarget :: x86_64-unknown-linux-gnu-LTO :: offloading/std_complex_arithmetic.cpp (875 of 879)
command timed out: 1200 seconds without output running [b'ninja', b'-j 32', b'check-offload'], attempting to kill
process killed by signal 9
program finished with exit code -1
elapsedTime=1237.864657