[llvm-branch-commits] [llvm] d90afbc - Revert "[SLP] Check for PHI nodes (potentially cycles!) when checking dependencies"

Tom Stellard via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Fri Feb 14 17:28:45 PST 2025


Author: Tom Stellard
Date: 2025-02-14T17:28:02-08:00
New Revision: d90afbca9367ef98273e1b3dae7fa26766e0335d

URL: https://github.com/llvm/llvm-project/commit/d90afbca9367ef98273e1b3dae7fa26766e0335d
DIFF: https://github.com/llvm/llvm-project/commit/d90afbca9367ef98273e1b3dae7fa26766e0335d.diff

LOG: Revert "[SLP] Check for PHI nodes (potentially cycles!) when checking dependencies"

This reverts commit 2eb558c99d967af093340def231c9a1ba228571b.

This commit did not pass pre-commit CI.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    llvm/test/Transforms/SLPVectorizer/X86/delayed-gather-emission.ll
    llvm/test/Transforms/SLPVectorizer/X86/matching-gather-nodes-phi-users.ll

Removed: 
    llvm/test/Transforms/SLPVectorizer/X86/phi-node-with-cycle.ll


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 7b20eda550095..19963e780ebd3 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -13181,16 +13181,8 @@ BoUpSLP::isGatherShuffledSingleRegisterEntry(
           continue;
         // If the user instruction is used for some reason in 
diff erent
         // vectorized nodes - make it depend on index.
-        // If any vector node is PHI node, this dependency might not work
-        // because of cycle dependencies, so disable it.
         if (TEUseEI.UserTE != UseEI.UserTE &&
-            (TEUseEI.UserTE->Idx < UseEI.UserTE->Idx ||
-             any_of(
-                 VectorizableTree,
-                 [](const std::unique_ptr<TreeEntry> &TE) {
-                   return TE->State == TreeEntry::Vectorize &&
-                          TE->getOpcode() == Instruction::PHI;
-                 })))
+            TEUseEI.UserTE->Idx < UseEI.UserTE->Idx)
           continue;
       }
 

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/delayed-gather-emission.ll b/llvm/test/Transforms/SLPVectorizer/X86/delayed-gather-emission.ll
index bf3f0c4df74e4..5562291dbb6be 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/delayed-gather-emission.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/delayed-gather-emission.ll
@@ -31,7 +31,7 @@ define void @test() {
 ; CHECK-NEXT:    [[TOBOOL:%.*]] = fcmp une float [[I2]], 0.000000e+00
 ; CHECK-NEXT:    [[TMP8:%.*]] = shufflevector <2 x float> [[TMP5]], <2 x float> poison, <2 x i32> <i32 poison, i32 0>
 ; CHECK-NEXT:    [[TMP9]] = insertelement <2 x float> [[TMP8]], float [[I2]], i32 0
-; CHECK-NEXT:    [[TMP10]] = insertelement <2 x float> [[TMP2]], float [[I2]], i32 0
+; CHECK-NEXT:    [[TMP10]] = shufflevector <2 x float> [[TMP9]], <2 x float> [[TMP2]], <2 x i32> <i32 0, i32 3>
 ; CHECK-NEXT:    br i1 [[TOBOOL]], label [[BB1]], label [[BB2]]
 ;
 entry:

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/matching-gather-nodes-phi-users.ll b/llvm/test/Transforms/SLPVectorizer/X86/matching-gather-nodes-phi-users.ll
index d649465c9ff12..166c819098c8c 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/matching-gather-nodes-phi-users.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/matching-gather-nodes-phi-users.ll
@@ -8,7 +8,7 @@
 ; YAML: Function:        test
 ; YAML: Args:
 ; YAML:   - String:          'Stores SLP vectorized with cost '
-; YAML:   - Cost:            '-3'
+; YAML:   - Cost:            '-6'
 ; YAML:   - String:          ' and with tree size '
 ; YAML:   - TreeSize:        '14'
 ; YAML: ...

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/phi-node-with-cycle.ll b/llvm/test/Transforms/SLPVectorizer/X86/phi-node-with-cycle.ll
deleted file mode 100644
index 22e7e6a8e6624..0000000000000
--- a/llvm/test/Transforms/SLPVectorizer/X86/phi-node-with-cycle.ll
+++ /dev/null
@@ -1,59 +0,0 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
-; RUN: opt -S --passes=slp-vectorizer -mtriple=x86_64-unknown-linux-gnu -mcpu=haswell < %s | FileCheck %s
-
-define void @test(float %0) {
-; CHECK-LABEL: define void @test(
-; CHECK-SAME: float [[TMP0:%.*]]) #[[ATTR0:[0-9]+]] {
-; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <2 x float> <float 0.000000e+00, float poison>, float [[TMP0]], i32 1
-; CHECK-NEXT:    [[TMP3:%.*]] = fdiv <2 x float> [[TMP2]], zeroinitializer
-; CHECK-NEXT:    [[TMP4:%.*]] = insertelement <2 x float> <float poison, float 0.000000e+00>, float [[TMP0]], i32 0
-; CHECK-NEXT:    [[TMP5:%.*]] = fdiv <2 x float> [[TMP4]], zeroinitializer
-; CHECK-NEXT:    br label %[[BB6:.*]]
-; CHECK:       [[BB6]]:
-; CHECK-NEXT:    [[TMP7:%.*]] = fmul <2 x float> [[TMP5]], zeroinitializer
-; CHECK-NEXT:    [[TMP8:%.*]] = fsub <2 x float> zeroinitializer, [[TMP7]]
-; CHECK-NEXT:    br label %[[BB10:.*]]
-; CHECK:       [[BB9:.*]]:
-; CHECK-NEXT:    br label %[[BB10]]
-; CHECK:       [[BB10]]:
-; CHECK-NEXT:    [[TMP11:%.*]] = phi <2 x float> [ [[TMP8]], %[[BB6]] ], [ poison, %[[BB9]] ]
-; CHECK-NEXT:    br label %[[BB12:.*]]
-; CHECK:       [[BB12]]:
-; CHECK-NEXT:    [[TMP13:%.*]] = fmul <2 x float> [[TMP3]], zeroinitializer
-; CHECK-NEXT:    [[TMP14:%.*]] = fsub <2 x float> [[TMP11]], [[TMP13]]
-; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <2 x float> [[TMP14]], i32 0
-; CHECK-NEXT:    [[TMP16:%.*]] = extractelement <2 x float> [[TMP14]], i32 1
-; CHECK-NEXT:    [[TMP17:%.*]] = fadd float [[TMP15]], [[TMP16]]
-; CHECK-NEXT:    [[TMP18:%.*]] = call float @llvm.fabs.f32(float [[TMP17]])
-; CHECK-NEXT:    ret void
-;
-  %2 = fdiv float 0.000000e+00, 0.000000e+00
-  %3 = fdiv float 0.000000e+00, 0.000000e+00
-  %4 = fdiv float %0, 0.000000e+00
-  br label %5
-
-5:
-  %6 = fmul float %4, 0.000000e+00
-  %7 = fsub float 0.000000e+00, %6
-  %8 = fmul float %3, 0.000000e+00
-  %9 = fsub float 0.000000e+00, %8
-  br label %11
-
-10:
-  br label %11
-
-11:
-  %12 = phi float [ %7, %5 ], [ 0.000000e+00, %10 ]
-  %13 = phi float [ %9, %5 ], [ 0.000000e+00, %10 ]
-  br label %14
-
-14:
-  %15 = fmul float %2, 0.000000e+00
-  %16 = fsub float %12, %15
-  %17 = fmul float %4, 0.000000e+00
-  %18 = fsub float %13, %17
-  %19 = fadd float %16, %18
-  %20 = call float @llvm.fabs.f32(float %19)
-  ret void
-}
-


        


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