[ConstraintElim] Replace custom GEP index handling by using existing code

Instead of duplicating the existing decomposition code for GEP indices
just use the existing code by calling the existing decompose function on
the index expression and multiply the result's coefficients by the scale of
the index.

This both reduces code duplication and generalizes the pattern we can
handle.

diff --git a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
index db1da1f..1be2358 100644 (file)
--- a/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstraintElimination.cpp
@@ -265,55 +265,20 @@ decomposeGEP(GetElementPtrInst &GEP,
     // For an array/pointer, add the element offset, explicitly scaled.
     unsigned Scale = DL.getTypeAllocSize(GTI.getIndexedType()).getFixedSize();
 
-    Value *Op0, *Op1;
-    ConstantInt *CI;
-    // If the index is zero-extended, it is guaranteed to be positive.
-    if (match(Index, m_ZExt(m_Value(Op0)))) {
-      if (match(Op0, m_NUWShl(m_Value(Op1), m_ConstantInt(CI))) &&
-          canUseSExt(CI)) {
-        Result.emplace_back(
-            multiplyWithOverflow(
-                Scale, int64_t(std::pow(int64_t(2), CI->getSExtValue()))),
-            Op1);
-        continue;
-      }
-
-      if (match(Op0, m_NSWAdd(m_Value(Op1), m_ConstantInt(CI))) &&
-          canUseSExt(CI) && match(Op0, m_NUWAdd(m_Value(), m_Value()))) {
-        Result[0].Coefficient +=
-            multiplyWithOverflow(Scale, CI->getSExtValue());
-        Result.emplace_back(Scale, Op1);
-        continue;
-      }
-
-      Result.emplace_back(Scale, Op0, true);
-      continue;
-    }
-
-    if (match(Index, m_ConstantInt(CI)) && !CI->isNegative() &&
-        canUseSExt(CI)) {
-      Result[0].Coefficient += multiplyWithOverflow(Scale, CI->getSExtValue());
-      continue;
-    }
-
-    if (match(Index, m_NSWShl(m_Value(Op0), m_ConstantInt(CI))) &&
-        canUseSExt(CI)) {
-      Result.emplace_back(
-          multiplyWithOverflow(
-              Scale, int64_t(std::pow(int64_t(2), CI->getSExtValue()))),
-          Op0);
-    } else if (match(Index, m_NSWAdd(m_Value(Op0), m_ConstantInt(CI))) &&
-               canUseSExt(CI)) {
-      Result[0].Coefficient += multiplyWithOverflow(Scale, CI->getSExtValue());
-      Result.emplace_back(Scale, Op0);
+    auto IdxResult = decompose(Index, Preconditions, IsSigned, DL);
+    if (IdxResult.empty()) {
+      Result.emplace_back(Scale, Index);
     } else {
-      Op0 = Index;
-      Result.emplace_back(Scale, Op0);
+      for (auto &KV : IdxResult)
+        KV.Coefficient *= Scale;
+      Result[0].Coefficient += IdxResult[0].Coefficient;
+      append_range(Result, ArrayRef<DecompEntry>(IdxResult).drop_front());
     }
     // If Op0 is signed non-negative, the GEP is increasing monotonically and
     // can be de-composed.
-    Preconditions.emplace_back(CmpInst::ICMP_SGE, Op0,
-                               ConstantInt::get(Op0->getType(), 0));
+    if (!isKnownNonNegative(Index, DL, /*Depth=*/MaxAnalysisRecursionDepth - 1))
+      Preconditions.emplace_back(CmpInst::ICMP_SGE, Index,
+                                 ConstantInt::get(Index->getType(), 0));
   }
   return Result;
 }

diff --git a/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-different-types.ll b/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-different-types.ll
index 3cc3e03..149a9bc 100644 (file)
--- a/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-different-types.ll
+++ b/llvm/test/Transforms/ConstraintElimination/gep-arithmetic-different-types.ll
@@ -136,7 +136,7 @@ define i1 @gep_shl_nsw_positive_index(ptr %A, ptr %upper, i8 %idx) {
 ; CHECK-NEXT:    [[C_1:%.*]] = icmp ult ptr [[ADD_I32_IDX_1]], [[UPPER]]
 ; CHECK-NEXT:    [[ADD_I8_IDX_1:%.*]] = getelementptr inbounds i8, ptr [[A]], i8 [[IDX_1]]
 ; CHECK-NEXT:    [[T_1:%.*]] = icmp ult ptr [[ADD_I8_IDX_1]], [[UPPER]]
-; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 [[C_1]], true
+; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 [[C_1]], [[T_1]]
 ; CHECK-NEXT:    ret i1 [[RES_1]]
 ;
   %idx.pos = icmp sge i8 %idx, 0
@@ -208,7 +208,7 @@ define i1 @gep_zext_add_nuw_index(ptr %A, ptr %upper, i8 %idx) {
 ; CHECK-NEXT:    [[C_1:%.*]] = icmp ult ptr [[ADD_I32_IDX_1]], [[UPPER]]
 ; CHECK-NEXT:    [[ADD_I8_IDX_1:%.*]] = getelementptr inbounds i8, ptr [[A]], i16 [[IDX_1_EXT]]
 ; CHECK-NEXT:    [[T_1:%.*]] = icmp ult ptr [[ADD_I8_IDX_1]], [[UPPER]]
-; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 [[C_1]], [[T_1]]
+; CHECK-NEXT:    [[RES_1:%.*]] = xor i1 [[C_1]], true
 ; CHECK-NEXT:    ret i1 [[RES_1]]
 ;
   %idx.2 = add nuw i8 %idx, 2

diff --git a/llvm/test/Transforms/ConstraintElimination/geps-unsigned-predicates.ll b/llvm/test/Transforms/ConstraintElimination/geps-unsigned-predicates.ll
index 51eb96c..524a13f 100644 (file)
--- a/llvm/test/Transforms/ConstraintElimination/geps-unsigned-predicates.ll
+++ b/llvm/test/Transforms/ConstraintElimination/geps-unsigned-predicates.ll
@@ -513,7 +513,7 @@ define void @test.ult.gep.shl(ptr readonly %src, ptr readnone %max, i8 %idx) {
 ; CHECK-NEXT:    [[IDX_SHL_1:%.*]] = shl nuw nsw i8 [[IDX]], 1
 ; CHECK-NEXT:    [[ADD_PTR_SHL_1:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i8 [[IDX_SHL_1]]
 ; CHECK-NEXT:    [[C_MAX_0:%.*]] = icmp ult ptr [[ADD_PTR_SHL_1]], [[MAX]]
-; CHECK-NEXT:    call void @use(i1 true)
+; CHECK-NEXT:    call void @use(i1 [[C_MAX_0]])
 ; CHECK-NEXT:    [[IDX_SHL_2:%.*]] = shl nuw i8 [[IDX]], 2
 ; CHECK-NEXT:    [[ADD_PTR_SHL_2:%.*]] = getelementptr inbounds i32, ptr [[SRC]], i8 [[IDX_SHL_2]]
 ; CHECK-NEXT:    [[C_MAX_1:%.*]] = icmp ult ptr [[ADD_PTR_SHL_2]], [[MAX]]

diff --git a/llvm/test/Transforms/ConstraintElimination/large-constant-ints.ll b/llvm/test/Transforms/ConstraintElimination/large-constant-ints.ll
index 32c5383..9c65f0e 100644 (file)
--- a/llvm/test/Transforms/ConstraintElimination/large-constant-ints.ll
+++ b/llvm/test/Transforms/ConstraintElimination/large-constant-ints.ll
@@ -132,7 +132,7 @@ define i1 @gep_decomp_i80(ptr %a) {
 ; CHECK:       then:
 ; CHECK-NEXT:    [[GEP_1:%.*]] = getelementptr inbounds i8, ptr [[A]], i80 1973801615886922022913
 ; CHECK-NEXT:    [[C_1:%.*]] = icmp eq ptr [[GEP_1]], null
-; CHECK-NEXT:    ret i1 [[C_1]]
+; CHECK-NEXT:    ret i1 true
 ; CHECK:       else:
 ; CHECK-NEXT:    ret i1 false
 ;