[PATCH] D30587: [LV] Delete unneeded scalar GEP creation code

[Matthew Simpson via Phabricator via llvm-commits]

mssimpso created this revision.
Herald added a subscriber: mzolotukhin.

The code for generating scalar base pointers in vectorizeMemoryInstruction is not needed. We currently scalarize all GEPs and maintain the scalarized values in VectorLoopValueMap. The GEP cloning in this unneeded code is the same as that in scalarizeInstruction. The test cases that changed as a result of this patch changed because we were able to reuse the scalarized GEP that we previously generated instead of cloning a new one.

I plan to follow this patch up with a few more that will eventually merge pointer induction variable widening with the rest of the induction widening code.


https://reviews.llvm.org/D30587

Files:
  lib/Transforms/Vectorize/LoopVectorize.cpp
  test/Transforms/LoopVectorize/float-induction.ll
  test/Transforms/LoopVectorize/if-pred-stores.ll


Index: test/Transforms/LoopVectorize/if-pred-stores.ll
===================================================================
--- test/Transforms/LoopVectorize/if-pred-stores.ll
+++ test/Transforms/LoopVectorize/if-pred-stores.ll
@@ -11,6 +11,7 @@
 
 ; VEC-LABEL: test
 ; VEC:   %[[v0:.+]] = add i64 %index, 0
+; VEC:   %[[v2:.+]] = getelementptr inbounds i32, i32* %f, i64 %[[v0]]
 ; VEC:   %[[v8:.+]] = icmp sgt <2 x i32> %{{.*}}, <i32 100, i32 100>
 ; VEC:   %[[v10:.+]] = and <2 x i1> %[[v8]], <i1 true, i1 true>
 ; VEC:   %[[o1:.+]] = or <2 x i1> zeroinitializer, %[[v10]]
@@ -21,7 +22,6 @@
 ; VEC: [[cond]]:
 ; VEC:   %[[v13:.+]] = extractelement <2 x i32> %wide.load, i32 0
 ; VEC:   %[[v9a:.+]] = add nsw i32 %[[v13]], 20
-; VEC:   %[[v2:.+]] = getelementptr inbounds i32, i32* %f, i64 %[[v0]]
 ; VEC:   store i32 %[[v9a]], i32* %[[v2]], align 4
 ; VEC:   br label %[[else:.+]]
 ;
Index: test/Transforms/LoopVectorize/float-induction.ll
===================================================================
--- test/Transforms/LoopVectorize/float-induction.ll
+++ test/Transforms/LoopVectorize/float-induction.ll
@@ -298,8 +298,7 @@
 ; VEC2_INTERL1_PRED_STORE-NEXT:    [[TMP5:%.*]] = extractelement <2 x i1> [[TMP4]], i32 0
 ; VEC2_INTERL1_PRED_STORE-NEXT:    br i1 [[TMP5]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
 ; VEC2_INTERL1_PRED_STORE:       [[PRED_STORE_IF]]:
-; VEC2_INTERL1_PRED_STORE-NEXT:    [[TMP7:%.*]] = getelementptr inbounds float, float* %A, i64 [[INDEX]]
-; VEC2_INTERL1_PRED_STORE-NEXT:    store float [[TMP1]], float* [[TMP7]], align 4
+; VEC2_INTERL1_PRED_STORE-NEXT:    store float [[TMP1]], float* [[TMP2]], align 4
 ; VEC2_INTERL1_PRED_STORE-NEXT:    br label %[[PRED_STORE_CONTINUE]]
 ; VEC2_INTERL1_PRED_STORE:       [[PRED_STORE_CONTINUE]]:
 ; VEC2_INTERL1_PRED_STORE-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP4]], i32 1
Index: lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- lib/Transforms/Vectorize/LoopVectorize.cpp
+++ lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2963,39 +2963,7 @@
   // Handle consecutive loads/stores.
   GetElementPtrInst *Gep = getGEPInstruction(Ptr);
   if (ConsecutiveStride) {
-    if (Gep) {
-      unsigned NumOperands = Gep->getNumOperands();
-#ifndef NDEBUG
-      // The original GEP that identified as a consecutive memory access
-      // should have only one loop-variant operand.
-      unsigned NumOfLoopVariantOps = 0;
-      for (unsigned i = 0; i < NumOperands; ++i)
-        if (!PSE.getSE()->isLoopInvariant(PSE.getSCEV(Gep->getOperand(i)),
-                                          OrigLoop))
-          NumOfLoopVariantOps++;
-      assert(NumOfLoopVariantOps == 1 &&
-             "Consecutive GEP should have only one loop-variant operand");
-#endif
-      GetElementPtrInst *Gep2 = cast<GetElementPtrInst>(Gep->clone());
-      Gep2->setName("gep.indvar");
-
-      // A new GEP is created for a 0-lane value of the first unroll iteration.
-      // The GEPs for the rest of the unroll iterations are computed below as an
-      // offset from this GEP.
-      for (unsigned i = 0; i < NumOperands; ++i)
-        // We can apply getScalarValue() for all GEP indices. It returns an
-        // original value for loop-invariant operand and 0-lane for consecutive
-        // operand.
-        Gep2->setOperand(i, getScalarValue(Gep->getOperand(i),
-                                           0, /* First unroll iteration */
-                                           0  /* 0-lane of the vector */ ));
-      setDebugLocFromInst(Builder, Gep);
-      Ptr = Builder.Insert(Gep2);
-
-    } else { // No GEP
-      setDebugLocFromInst(Builder, Ptr);
-      Ptr = getScalarValue(Ptr, 0, 0);
-    }
+    Ptr = getScalarValue(Ptr, 0, 0);
   } else {
     // At this point we should vector version of GEP for Gather or Scatter
     assert(CreateGatherScatter && "The instruction should be scalarized");


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