[PATCH] D33129: [SCEVExpander] Try harder to avoid introducing inttoptr

[Keno Fischer via Phabricator via llvm-commits]

loladiro updated this revision to Diff 99267.
loladiro added a comment.

Changed the patch to do the argument re-arranging in the caller instead. I think
that's more localized to just this non-integral pointer change.


https://reviews.llvm.org/D33129

Files:
  lib/Analysis/ScalarEvolutionExpander.cpp
  test/Transforms/LoopStrengthReduce/nonintegral.ll


Index: test/Transforms/LoopStrengthReduce/nonintegral.ll
===================================================================
--- /dev/null
+++ test/Transforms/LoopStrengthReduce/nonintegral.ll
@@ -0,0 +1,45 @@
+; RUN: opt -S -loop-reduce < %s | FileCheck %s
+
+; Address Space 10 is non-integral. The optimizer is not allowed to use
+; ptrtoint/inttoptr instructions. Make sure that this doesn't happen
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128-ni:10:11:12"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @japi1__unsafe_getindex_65028(i64 addrspace(10)* %arg) {
+; CHECK-NOT: inttoptr
+; CHECK-NOT: ptrtoint
+; How exactly SCEV chooses to materialize isn't all that important, as
+; long as it doesn't try to round-trip through integers. As of this writing,
+; it emits a byte-wise gep, which is fine.
+; CHECK: getelementptr i8, i8 addrspace(10)* {{.*}}, i64 {{.*}}
+top:
+  br label %L86
+
+L86:                                              ; preds = %L86, %top
+  %i.0 = phi i64 [ 0, %top ], [ %0, %L86 ]
+  %0 = add i64 %i.0, 1
+  br i1 undef, label %L86, label %if29
+
+if29:                                             ; preds = %L86
+  %1 = shl i64 %0, 1
+  %2 = add i64 %1, -2
+  br label %if31
+
+if31:                                             ; preds = %if38, %if29
+  %"#temp#1.sroa.0.022" = phi i64 [ 0, %if29 ], [ %3, %if38 ]
+  br label %L119
+
+L119:                                             ; preds = %L119, %if31
+  %i5.0 = phi i64 [ %"#temp#1.sroa.0.022", %if31 ], [ %3, %L119 ]
+  %3 = add i64 %i5.0, 1
+  br i1 undef, label %L119, label %if38
+
+if38:                                             ; preds = %L119
+  %4 = add i64 %2, %i5.0
+  %5 = getelementptr i64, i64 addrspace(10)* %arg, i64 %4
+  %6 = load i64, i64 addrspace(10)* %5
+  br i1 undef, label %done, label %if31
+
+done:
+  ret void
+}
Index: lib/Analysis/ScalarEvolutionExpander.cpp
===================================================================
--- lib/Analysis/ScalarEvolutionExpander.cpp
+++ lib/Analysis/ScalarEvolutionExpander.cpp
@@ -1305,12 +1305,17 @@
   // Expand the core addrec. If we need post-loop scaling, force it to
   // expand to an integer type to avoid the need for additional casting.
   Type *ExpandTy = PostLoopScale ? IntTy : STy;
+  // We can't use a pointer type for the addrec if the pointer type is
+  // non-integral.
+  Type *AddRecPHIExpandTy =
+      DL.isNonIntegralPointerType(STy) ? Normalized->getType() : ExpandTy;
+
   // In some cases, we decide to reuse an existing phi node but need to truncate
   // it and/or invert the step.
   Type *TruncTy = nullptr;
   bool InvertStep = false;
-  PHINode *PN = getAddRecExprPHILiterally(Normalized, L, ExpandTy, IntTy,
-                                          TruncTy, InvertStep);
+  PHINode *PN = getAddRecExprPHILiterally(Normalized, L, AddRecPHIExpandTy,
+                                          IntTy, TruncTy, InvertStep);
 
   // Accommodate post-inc mode, if necessary.
   Value *Result;
@@ -1383,8 +1388,15 @@
   // Re-apply any non-loop-dominating offset.
   if (PostLoopOffset) {
     if (PointerType *PTy = dyn_cast<PointerType>(ExpandTy)) {
-      const SCEV *const OffsetArray[1] = { PostLoopOffset };
-      Result = expandAddToGEP(OffsetArray, OffsetArray+1, PTy, IntTy, Result);
+      if (Result->getType()->isIntegerTy()) {
+        Value *Base = expandCodeFor(PostLoopOffset, ExpandTy);
+        const SCEV *const OffsetArray[1] = {SE.getUnknown(Result)};
+        Result = expandAddToGEP(OffsetArray, OffsetArray + 1, PTy, IntTy, Base);
+      } else {
+        const SCEV *const OffsetArray[1] = {PostLoopOffset};
+        Result =
+            expandAddToGEP(OffsetArray, OffsetArray + 1, PTy, IntTy, Result);
+      }
     } else {
       Result = InsertNoopCastOfTo(Result, IntTy);
       Result = Builder.CreateAdd(Result,


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