[llvm] 90ea81f - [LV] Widen freeze instead of scalarizing it

[via llvm-commits]

Author: lizhijin
Date: 2022-05-19T12:28:01+08:00
New Revision: 90ea81fcb28e48c080e1a9016dd5262eeb33d0ce

URL: https://github.com/llvm/llvm-project/commit/90ea81fcb28e48c080e1a9016dd5262eeb33d0ce
DIFF: https://github.com/llvm/llvm-project/commit/90ea81fcb28e48c080e1a9016dd5262eeb33d0ce.diff

LOG: [LV] Widen freeze instead of scalarizing it

This patch changes the strategy for vectorizing freeze instrucion, from
replicating multiple times to widening according to selected VF.

Fixes #54992

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D125016

Added: 
    llvm/test/Transforms/LoopVectorize/vector-freeze.ll

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index d33bea47e0341..4bd3c2f35fe5d 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -8444,6 +8444,7 @@ VPWidenRecipe *VPRecipeBuilder::tryToWiden(Instruction *I,
     case Instruction::URem:
     case Instruction::Xor:
     case Instruction::ZExt:
+    case Instruction::Freeze:
       return true;
     }
     return false;
@@ -9367,6 +9368,17 @@ void VPWidenRecipe::execute(VPTransformState &State) {
 
     break;
   }
+  case Instruction::Freeze: {
+    State.ILV->setDebugLocFromInst(&I);
+
+    for (unsigned Part = 0; Part < State.UF; ++Part) {
+      Value *Op = State.get(getOperand(0), Part);
+
+      Value *Freeze = Builder.CreateFreeze(Op);
+      State.set(this, Freeze, Part);
+    }
+    break;
+  }
   case Instruction::ICmp:
   case Instruction::FCmp: {
     // Widen compares. Generate vector compares.

diff  --git a/llvm/test/Transforms/LoopVectorize/vector-freeze.ll b/llvm/test/Transforms/LoopVectorize/vector-freeze.ll
new file mode 100644
index 0000000000000..a1eb7b31a256f
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/vector-freeze.ll
@@ -0,0 +1,26 @@
+; RUN: opt -loop-vectorize -force-vector-width=16 -force-vector-interleave=1 -S < %s | FileCheck %s
+; RUN: opt -loop-vectorize -scalable-vectorization=on -force-target-supports-scalable-vectors=true -force-vector-width=16 -force-vector-interleave=1 -S < %s | FileCheck %s --check-prefix=SVE
+
+define i64 @test(ptr noalias readonly %addr) {
+; CHECK-LABEL: @test(
+; CHECK:       vector.body:
+; CHECK:       freeze <16 x i64>
+
+; SVE-LABEL: @test(
+; SVE:       vector.body:
+; SVE:       freeze <vscale x 16 x i64>
+
+entry:
+  br label %loop
+
+exit:
+  ret i64 %tmp4
+
+loop:
+  %tmp3 = phi ptr [ %tmp6, %loop ], [ %addr, %entry ]
+  %tmp4 = freeze i64 0
+  %tmp5 = add i64 0, 0
+  %tmp6 = getelementptr inbounds ptr, ptr %tmp3, i64 1
+  %tmp7 = icmp eq ptr %tmp6, null
+  br i1 %tmp7, label %exit, label %loop
+}