[llvm-branch-commits] [llvm] 183e8ec - [LV] Disable VPlan-based cost model for 19.x release.

[Tobias Hieta via llvm-branch-commits]

Author: Florian Hahn
Date: 2024-07-23T17:02:03+02:00
New Revision: 183e8ecc97a996c24e920e7e9668bc65a0d19439

URL: https://github.com/llvm/llvm-project/commit/183e8ecc97a996c24e920e7e9668bc65a0d19439
DIFF: https://github.com/llvm/llvm-project/commit/183e8ecc97a996c24e920e7e9668bc65a0d19439.diff

LOG: [LV] Disable VPlan-based cost model for 19.x release.

As discussed in  https://github.com/llvm/llvm-project/pull/92555 flip
the default for the option added in
https://github.com/llvm/llvm-project/pull/99536 to true.

This restores the original behavior for the release branch to give the
VPlan-based cost model more time to mature on main.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll
    llvm/test/tools/UpdateTestChecks/update_analyze_test_checks/Inputs/x86-loopvectorize-costmodel.ll.expected

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 6d28b8fabe42e..68363abdb817a 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -206,7 +206,7 @@ static cl::opt<unsigned> VectorizeMemoryCheckThreshold(
     cl::desc("The maximum allowed number of runtime memory checks"));
 
 static cl::opt<bool> UseLegacyCostModel(
-    "vectorize-use-legacy-cost-model", cl::init(false), cl::Hidden,
+    "vectorize-use-legacy-cost-model", cl::init(true), cl::Hidden,
     cl::desc("Use the legacy cost model instead of the VPlan-based cost model. "
              "This option will be removed in the future."));
 

diff  --git a/llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll b/llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll
index fc310f4163082..1a78eaf644723 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/riscv-vector-reverse.ll
@@ -135,7 +135,6 @@ define void @vector_reverse_i64(ptr nocapture noundef writeonly %A, ptr nocaptur
 ; CHECK-NEXT:  LV: Interleaving is not beneficial.
 ; CHECK-NEXT:  LV: Found a vectorizable loop (vscale x 4) in <stdin>
 ; CHECK-NEXT:  LEV: Epilogue vectorization is not profitable for this loop
-; CHECK-NEXT:  VF picked by VPlan cost model: vscale x 4
 ; CHECK-NEXT:  Executing best plan with VF=vscale x 4, UF=1
 ; CHECK-NEXT:  VPlan 'Final VPlan for VF={vscale x 4},UF>=1' {
 ; CHECK-NEXT:  Live-in vp<%0> = VF * UF
@@ -339,7 +338,6 @@ define void @vector_reverse_f32(ptr nocapture noundef writeonly %A, ptr nocaptur
 ; CHECK-NEXT:  LV: Interleaving is not beneficial.
 ; CHECK-NEXT:  LV: Found a vectorizable loop (vscale x 4) in <stdin>
 ; CHECK-NEXT:  LEV: Epilogue vectorization is not profitable for this loop
-; CHECK-NEXT:  VF picked by VPlan cost model: vscale x 4
 ; CHECK-NEXT:  Executing best plan with VF=vscale x 4, UF=1
 ; CHECK-NEXT:  VPlan 'Final VPlan for VF={vscale x 4},UF>=1' {
 ; CHECK-NEXT:  Live-in vp<%0> = VF * UF

diff  --git a/llvm/test/tools/UpdateTestChecks/update_analyze_test_checks/Inputs/x86-loopvectorize-costmodel.ll.expected b/llvm/test/tools/UpdateTestChecks/update_analyze_test_checks/Inputs/x86-loopvectorize-costmodel.ll.expected
index 5aa270e76f4c8..e862bf87d265c 100644
--- a/llvm/test/tools/UpdateTestChecks/update_analyze_test_checks/Inputs/x86-loopvectorize-costmodel.ll.expected
+++ b/llvm/test/tools/UpdateTestChecks/update_analyze_test_checks/Inputs/x86-loopvectorize-costmodel.ll.expected
@@ -17,7 +17,6 @@ define void @test() {
 ; CHECK:  LV: Found an estimated cost of 5 for VF 16 For instruction: %v0 = load float, ptr %in0, align 4
 ; CHECK:  LV: Found an estimated cost of 22 for VF 32 For instruction: %v0 = load float, ptr %in0, align 4
 ; CHECK:  LV: Found an estimated cost of 92 for VF 64 For instruction: %v0 = load float, ptr %in0, align 4
-; CHECK:  LV: Found an estimated cost of 1 for VF 1 For instruction: %v0 = load float, ptr %in0, align 4
 ;
 entry:
   br label %for.body