Recommit "[VP,Integer,#2] ExpandVectorPredication pass"

This reverts the revert 02c5ba8679873e878ae7a76fb26808a47940275b

Fix:

Pass was registered as DUMMY_FUNCTION_PASS causing the newpm-pass
functions to be doubly defined. Triggered in -DLLVM_ENABLE_MODULE=1
builds.

Original commit:

This patch implements expansion of llvm.vp.* intrinsics
(https://llvm.org/docs/LangRef.html#vector-predication-intrinsics).

VP expansion is required for targets that do not implement VP code
generation. Since expansion is controllable with TTI, targets can switch
on the VP intrinsics they do support in their backend offering a smooth
transition strategy for VP code generation (VE, RISC-V V, ARM SVE,
AVX512, ..).

Reviewed By: rogfer01

Differential Revision: https://reviews.llvm.org/D78203

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index 6e80235..b5e8f9e 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -864,6 +864,11 @@ void TargetPassConfig::addIRPasses() {
   if (getOptLevel() != CodeGenOpt::None && !DisablePartialLibcallInlining)
     addPass(createPartiallyInlineLibCallsPass());
 
+  // Expand vector predication intrinsics into standard IR instructions.
+  // This pass has to run before ScalarizeMaskedMemIntrin and ExpandReduction
+  // passes since it emits those kinds of intrinsics.
+  addPass(createExpandVectorPredicationPass());
+
   // Add scalarization of target's unsupported masked memory intrinsics pass.
   // the unsupported intrinsic will be replaced with a chain of basic blocks,
   // that stores/loads element one-by-one if the appropriate mask bit is set.