[llvm-commits] [llvm] r108475 - in /llvm/trunk: lib/Analysis/ScalarEvolutionExpander.cpp test/Transforms/IndVarSimplify/uglygep.ll

[Dan Gohman]

Author: djg
Date: Thu Jul 15 18:38:13 2010
New Revision: 108475

URL: http://llvm.org/viewvc/llvm-project?rev=108475&view=rev
Log:
Fix the order that SCEVExpander considers add operands in so that
it doesn't miss an opportunity to form a GEP, regardless of the
relative loop depths of the operands. This fixes rdar://8197217.

Added:
    llvm/trunk/test/Transforms/IndVarSimplify/uglygep.ll
Modified:
    llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp

Modified: llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp?rev=108475&r1=108474&r2=108475&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolutionExpander.cpp Thu Jul 15 18:38:13 2010
@@ -647,6 +647,11 @@
 
   bool operator()(std::pair<const Loop *, const SCEV *> LHS,
                   std::pair<const Loop *, const SCEV *> RHS) const {
+    // Keep pointer operands sorted at the end.
+    if (LHS.second->getType()->isPointerTy() !=
+        RHS.second->getType()->isPointerTy())
+      return LHS.second->getType()->isPointerTy();
+
     // Compare loops with PickMostRelevantLoop.
     if (LHS.first != RHS.first)
       return PickMostRelevantLoop(LHS.first, RHS.first, DT) != LHS.first;
@@ -699,8 +704,15 @@
       // The running sum expression is a pointer. Try to form a getelementptr
       // at this level with that as the base.
       SmallVector<const SCEV *, 4> NewOps;
-      for (; I != E && I->first == CurLoop; ++I)
-        NewOps.push_back(I->second);
+      for (; I != E && I->first == CurLoop; ++I) {
+        // If the operand is SCEVUnknown and not instructions, peek through
+        // it, to enable more of it to be folded into the GEP.
+        const SCEV *X = I->second;
+        if (const SCEVUnknown *U = dyn_cast<SCEVUnknown>(X))
+          if (!isa<Instruction>(U->getValue()))
+            X = SE.getSCEV(U->getValue());
+        NewOps.push_back(X);
+      }
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
     } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
       // The running sum is an integer, and there's a pointer at this level.

Added: llvm/trunk/test/Transforms/IndVarSimplify/uglygep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/IndVarSimplify/uglygep.ll?rev=108475&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/IndVarSimplify/uglygep.ll (added)
+++ llvm/trunk/test/Transforms/IndVarSimplify/uglygep.ll Thu Jul 15 18:38:13 2010
@@ -0,0 +1,40 @@
+; RUN: opt -indvars -S | not grep uglygep
+; rdar://8197217
+
+; Indvars should be able to emit a clean GEP here, not an uglygep.
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
+target triple = "x86_64-apple-darwin11.0"
+
+ at numf2s = external global i32                     ; <i32*> [#uses=1]
+ at numf1s = external global i32                     ; <i32*> [#uses=1]
+ at tds = external global double**                   ; <double***> [#uses=1]
+
+define void @init_td(i32 %tmp7) nounwind {
+entry:
+  br label %bb4
+
+bb4:                                              ; preds = %bb3, %entry
+  %i.0 = phi i32 [ 0, %entry ], [ %tmp9, %bb3 ]   ; <i32> [#uses=3]
+  br label %bb
+
+bb:                                               ; preds = %bb4
+  br label %bb2
+
+bb2:                                              ; preds = %bb1, %bb
+  %j.0 = phi i32 [ 0, %bb ], [ %tmp6, %bb1 ]      ; <i32> [#uses=3]
+  %tmp8 = icmp slt i32 %j.0, %tmp7                ; <i1> [#uses=1]
+  br i1 %tmp8, label %bb1, label %bb3
+
+bb1:                                              ; preds = %bb2
+  %tmp = load double*** @tds, align 8             ; <double**> [#uses=1]
+  %tmp1 = sext i32 %i.0 to i64                    ; <i64> [#uses=1]
+  %tmp2 = getelementptr inbounds double** %tmp, i64 %tmp1 ; <double**> [#uses=1]
+  %tmp3 = load double** %tmp2, align 1            ; <double*> [#uses=1]
+  %tmp6 = add nsw i32 %j.0, 1                     ; <i32> [#uses=1]
+  br label %bb2
+
+bb3:                                              ; preds = %bb2
+  %tmp9 = add nsw i32 %i.0, 1                     ; <i32> [#uses=1]
+  br label %bb4
+}