Avoid infinite looping in AllGlobalLoadUsesSimpleEnoughForHeapSRA(). This can happen...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72710 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 8a752c2b6c1c181c56c4f2cc3ca67a252505b520..2c01cc30bd69e1363a6f558f9cf35f9457ed6867 100644 (file)
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -1020,7 +1020,8 @@ static void ReplaceUsesOfMallocWithGlobal(Instruction *Alloc,
 /// of a load) are simple enough to perform heap SRA on.  This permits GEP's
 /// that index through the array and struct field, icmps of null, and PHIs.
 static bool LoadUsesSimpleEnoughForHeapSRA(Value *V,
-                                     SmallPtrSet<PHINode*, 32> &LoadUsingPHIs) {
+                              SmallPtrSet<PHINode*, 32> &LoadUsingPHIs,
+                              SmallPtrSet<PHINode*, 32> &LoadUsingPHIsPerLoad) {
   // We permit two users of the load: setcc comparing against the null
   // pointer, and a getelementptr of a specific form.
   for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
@@ -1044,12 +1045,17 @@ static bool LoadUsesSimpleEnoughForHeapSRA(Value *V,
     }
     
     if (PHINode *PN = dyn_cast<PHINode>(User)) {
-      // If we have already recursively analyzed this PHI, then it is safe.
-      if (LoadUsingPHIs.insert(PN))
+      if (!LoadUsingPHIsPerLoad.insert(PN))
+        // This means some phi nodes are dependent on each other.
+        // Avoid infinite looping!
+        return false;
+      if (!LoadUsingPHIs.insert(PN))
+        // If we have already analyzed this PHI, then it is safe.
         continue;
       
       // Make sure all uses of the PHI are simple enough to transform.
-      if (!LoadUsesSimpleEnoughForHeapSRA(PN, LoadUsingPHIs))
+      if (!LoadUsesSimpleEnoughForHeapSRA(PN,
+                                          LoadUsingPHIs, LoadUsingPHIsPerLoad))
         return false;
       
       continue;
@@ -1068,11 +1074,15 @@ static bool LoadUsesSimpleEnoughForHeapSRA(Value *V,
 static bool AllGlobalLoadUsesSimpleEnoughForHeapSRA(GlobalVariable *GV,
                                                     MallocInst *MI) {
   SmallPtrSet<PHINode*, 32> LoadUsingPHIs;
+  SmallPtrSet<PHINode*, 32> LoadUsingPHIsPerLoad;
   for (Value::use_iterator UI = GV->use_begin(), E = GV->use_end(); UI != E; 
        ++UI)
-    if (LoadInst *LI = dyn_cast<LoadInst>(*UI))
-      if (!LoadUsesSimpleEnoughForHeapSRA(LI, LoadUsingPHIs))
+    if (LoadInst *LI = dyn_cast<LoadInst>(*UI)) {
+      if (!LoadUsesSimpleEnoughForHeapSRA(LI, LoadUsingPHIs,
+                                          LoadUsingPHIsPerLoad))
         return false;
+      LoadUsingPHIsPerLoad.clear();
+    }
   
   // If we reach here, we know that all uses of the loads and transitive uses
   // (through PHI nodes) are simple enough to transform.  However, we don't know

diff --git a/test/Transforms/GlobalOpt/2009-06-01-RecursivePHI.ll b/test/Transforms/GlobalOpt/2009-06-01-RecursivePHI.ll
new file mode 100644 (file)
index 0000000..0ce16dd
--- /dev/null
+++ b/test/Transforms/GlobalOpt/2009-06-01-RecursivePHI.ll
@@ -0,0 +1,117 @@
+; RUN: llvm-as < %s | opt -globalopt
+
+       %struct.s_annealing_sched = type { i32, float, float, float, float }
+       %struct.s_bb = type { i32, i32, i32, i32 }
+       %struct.s_net = type { i8*, i32, i32*, float, float }
+       %struct.s_placer_opts = type { i32, float, i32, i32, i8*, i32, i32 }
+@net = internal global %struct.s_net* null             ; <%struct.s_net**> [#uses=4]
+
+define fastcc void @alloc_and_load_placement_structs(i32 %place_cost_type, i32 %num_regions, float %place_cost_exp, float*** nocapture %old_region_occ_x, float*** nocapture %old_region_occ_y) nounwind ssp {
+entry:
+       br i1 undef, label %bb.i, label %my_malloc.exit
+
+bb.i:          ; preds = %entry
+       unreachable
+
+my_malloc.exit:                ; preds = %entry
+       br i1 undef, label %bb.i81, label %my_malloc.exit83
+
+bb.i81:                ; preds = %my_malloc.exit
+       unreachable
+
+my_malloc.exit83:              ; preds = %my_malloc.exit
+       br i1 undef, label %bb.i.i57, label %my_calloc.exit.i
+
+bb.i.i57:              ; preds = %my_malloc.exit83
+       unreachable
+
+my_calloc.exit.i:              ; preds = %my_malloc.exit83
+       br i1 undef, label %bb.i4.i, label %my_calloc.exit5.i
+
+bb.i4.i:               ; preds = %my_calloc.exit.i
+       unreachable
+
+my_calloc.exit5.i:             ; preds = %my_calloc.exit.i
+       %.pre.i58 = load %struct.s_net** @net, align 4          ; <%struct.s_net*> [#uses=1]
+       br label %bb17.i78
+
+bb1.i61:               ; preds = %bb4.preheader.i, %bb1.i61
+       br i1 undef, label %bb1.i61, label %bb5.i62
+
+bb5.i62:               ; preds = %bb1.i61
+       br i1 undef, label %bb6.i64, label %bb15.preheader.i
+
+bb15.preheader.i:              ; preds = %bb4.preheader.i, %bb5.i62
+       br label %bb16.i77
+
+bb6.i64:               ; preds = %bb5.i62
+       br i1 undef, label %bb7.i65, label %bb8.i67
+
+bb7.i65:               ; preds = %bb6.i64
+       unreachable
+
+bb8.i67:               ; preds = %bb6.i64
+       br i1 undef, label %bb.i1.i68, label %my_malloc.exit.i70
+
+bb.i1.i68:             ; preds = %bb8.i67
+       unreachable
+
+my_malloc.exit.i70:            ; preds = %bb8.i67
+       %0 = load %struct.s_net** @net, align 4         ; <%struct.s_net*> [#uses=1]
+       br i1 undef, label %bb9.i71, label %bb16.i77
+
+bb9.i71:               ; preds = %bb9.i71, %my_malloc.exit.i70
+       %1 = load %struct.s_net** @net, align 4         ; <%struct.s_net*> [#uses=1]
+       br i1 undef, label %bb9.i71, label %bb16.i77
+
+bb16.i77:              ; preds = %bb9.i71, %my_malloc.exit.i70, %bb15.preheader.i
+       %.pre41.i.rle244 = phi %struct.s_net* [ %.pre41.i, %bb15.preheader.i ], [ %0, %my_malloc.exit.i70 ], [ %1, %bb9.i71 ]           ; <%struct.s_net*> [#uses=1]
+       br label %bb17.i78
+
+bb17.i78:              ; preds = %bb16.i77, %my_calloc.exit5.i
+       %.pre41.i = phi %struct.s_net* [ %.pre41.i.rle244, %bb16.i77 ], [ %.pre.i58, %my_calloc.exit5.i ]               ; <%struct.s_net*> [#uses=1]
+       br i1 undef, label %bb4.preheader.i, label %alloc_and_load_unique_pin_list.exit
+
+bb4.preheader.i:               ; preds = %bb17.i78
+       br i1 undef, label %bb1.i61, label %bb15.preheader.i
+
+alloc_and_load_unique_pin_list.exit:           ; preds = %bb17.i78
+       ret void
+}
+
+define void @read_net(i8* %net_file) nounwind ssp {
+entry:
+       br i1 undef, label %bb3.us.us.i, label %bb6.preheader
+
+bb6.preheader:         ; preds = %entry
+       br i1 undef, label %bb7, label %bb
+
+bb3.us.us.i:           ; preds = %entry
+       unreachable
+
+bb:            ; preds = %bb6.preheader
+       br i1 undef, label %bb.i34, label %bb1.i38
+
+bb.i34:                ; preds = %bb
+       unreachable
+
+bb1.i38:               ; preds = %bb
+       %0 = malloc %struct.s_net, i32 undef            ; <%struct.s_net*> [#uses=1]
+       br i1 undef, label %bb.i1.i39, label %my_malloc.exit2.i
+
+bb.i1.i39:             ; preds = %bb1.i38
+       unreachable
+
+my_malloc.exit2.i:             ; preds = %bb1.i38
+       store %struct.s_net* %0, %struct.s_net** @net, align 4
+       br i1 undef, label %bb.i7.i40, label %my_malloc.exit8.i
+
+bb.i7.i40:             ; preds = %my_malloc.exit2.i
+       unreachable
+
+my_malloc.exit8.i:             ; preds = %my_malloc.exit2.i
+       unreachable
+
+bb7:           ; preds = %bb6.preheader
+       unreachable
+}