Extend CaptureTracking to indicate when a value is never stored, even

if it is not ultimately captured. Teach BasicAliasAnalysis that a 
local object address which does not escape and is never stored does
not alias with a value resulting from a load.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89398 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 108 insertions, 0 deletions

diff --git a/test/Transforms/GVN/nonescaping-malloc.ll b/test/Transforms/GVN/nonescaping-malloc.ll
new file mode 100644
index 0000000..8a1cd6e
--- /dev/null
+++ b/test/Transforms/GVN/nonescaping-malloc.ll
@@ -0,0 +1,108 @@
+; RUN: opt < %s -gvn -stats |& grep {Number of loads deleted}
+; rdar://7363102
+
+; GVN should be able to eliminate load %tmp22.i, because it is redundant with
+; load %tmp8.i. This requires being able to prove that %tmp7.i doesn't
+; alias the malloc'd value %tmp.i20.i.i, which it can do since %tmp7.i
+; is derived from %tmp5.i which is computed from a load, and %tmp.i20.i.i
+; is never stored and does not escape.
+
+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"
+target triple = "x86_64-apple-darwin10.0"
+
+%"struct.llvm::MallocAllocator" = type <{ i8 }>
+%"struct.llvm::StringMap<void*,llvm::MallocAllocator>" = type { %"struct.llvm::StringMapImpl", %"struct.llvm::MallocAllocator" }
+%"struct.llvm::StringMapEntry<void*>" = type { %"struct.llvm::StringMapEntryBase", i8* }
+%"struct.llvm::StringMapEntryBase" = type { i32 }
+%"struct.llvm::StringMapImpl" = type { %"struct.llvm::StringMapImpl::ItemBucket"*, i32, i32, i32, i32 }
+%"struct.llvm::StringMapImpl::ItemBucket" = type { i32, %"struct.llvm::StringMapEntryBase"* }
+%"struct.llvm::StringRef" = type { i8*, i64 }
+
+define %"struct.llvm::StringMapEntry<void*>"* @_Z3fooRN4llvm9StringMapIPvNS_15MallocAllocatorEEEPKc(%"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %X, i8* %P) ssp {
+entry:
+  %tmp = alloca %"struct.llvm::StringRef", align 8 ; <%"struct.llvm::StringRef"*> [#uses=3]
+  %tmp.i = getelementptr inbounds %"struct.llvm::StringRef"* %tmp, i64 0, i32 0 ; <i8**> [#uses=1]
+  store i8* %P, i8** %tmp.i, align 8
+  %tmp1.i = call i64 @strlen(i8* %P) nounwind readonly ; <i64> [#uses=1]
+  %tmp2.i = getelementptr inbounds %"struct.llvm::StringRef"* %tmp, i64 0, i32 1 ; <i64*> [#uses=1]
+  store i64 %tmp1.i, i64* %tmp2.i, align 8
+  %tmp1 = call %"struct.llvm::StringMapEntry<void*>"* @_ZN4llvm9StringMapIPvNS_15MallocAllocatorEE16GetOrCreateValueERKNS_9StringRefE(%"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %X, %"struct.llvm::StringRef"* %tmp) ssp ; <%"struct.llvm::StringMapEntry<void*>"*> [#uses=1]
+  ret %"struct.llvm::StringMapEntry<void*>"* %tmp1
+}
+
+declare i64 @strlen(i8* nocapture) nounwind readonly
+
+declare noalias i8* @malloc(i64) nounwind
+
+declare void @llvm.memcpy.i64(i8* nocapture, i8* nocapture, i64, i32) nounwind
+
+declare i32 @_ZN4llvm13StringMapImpl15LookupBucketForENS_9StringRefE(%"struct.llvm::StringMapImpl"*, i64, i64)
+
+define linkonce_odr %"struct.llvm::StringMapEntry<void*>"* @_ZN4llvm9StringMapIPvNS_15MallocAllocatorEE16GetOrCreateValueERKNS_9StringRefE(%"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %this, %"struct.llvm::StringRef"* nocapture %Key) ssp align 2 {
+entry:
+  %elt = bitcast %"struct.llvm::StringRef"* %Key to i64* ; <i64*> [#uses=1]
+  %val = load i64* %elt                           ; <i64> [#uses=3]
+  %tmp = getelementptr inbounds %"struct.llvm::StringRef"* %Key, i64 0, i32 1 ; <i64*> [#uses=1]
+  %val2 = load i64* %tmp                          ; <i64> [#uses=2]
+  %tmp2.i = getelementptr inbounds %"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %this, i64 0, i32 0 ; <%"struct.llvm::StringMapImpl"*> [#uses=1]
+  %tmp3.i = tail call i32 @_ZN4llvm13StringMapImpl15LookupBucketForENS_9StringRefE(%"struct.llvm::StringMapImpl"* %tmp2.i, i64 %val, i64 %val2) ; <i32> [#uses=1]
+  %tmp4.i = getelementptr inbounds %"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %this, i64 0, i32 0, i32 0 ; <%"struct.llvm::StringMapImpl::ItemBucket"**> [#uses=1]
+  %tmp5.i = load %"struct.llvm::StringMapImpl::ItemBucket"** %tmp4.i, align 8 ; <%"struct.llvm::StringMapImpl::ItemBucket"*> [#uses=1]
+  %tmp6.i = zext i32 %tmp3.i to i64               ; <i64> [#uses=1]
+  %tmp7.i = getelementptr inbounds %"struct.llvm::StringMapImpl::ItemBucket"* %tmp5.i, i64 %tmp6.i, i32 1 ; <%"struct.llvm::StringMapEntryBase"**> [#uses=2]
+  %tmp8.i = load %"struct.llvm::StringMapEntryBase"** %tmp7.i, align 8 ; <%"struct.llvm::StringMapEntryBase"*> [#uses=3]
+  %tmp9.i = icmp eq %"struct.llvm::StringMapEntryBase"* %tmp8.i, null ; <i1> [#uses=1]
+  %tmp13.i = icmp eq %"struct.llvm::StringMapEntryBase"* %tmp8.i, inttoptr (i64 -1 to %"struct.llvm::StringMapEntryBase"*) ; <i1> [#uses=1]
+  %or.cond.i = or i1 %tmp9.i, %tmp13.i            ; <i1> [#uses=1]
+  br i1 %or.cond.i, label %bb4.i, label %bb6.i
+
+bb4.i:                                            ; preds = %entry
+  %tmp41.i = inttoptr i64 %val to i8*             ; <i8*> [#uses=2]
+  %tmp4.i35.i = getelementptr inbounds i8* %tmp41.i, i64 %val2 ; <i8*> [#uses=1]
+  %tmp.i.i = ptrtoint i8* %tmp4.i35.i to i64      ; <i64> [#uses=1]
+  %tmp1.i.i = trunc i64 %tmp.i.i to i32           ; <i32> [#uses=1]
+  %tmp3.i.i = trunc i64 %val to i32               ; <i32> [#uses=1]
+  %tmp4.i.i = sub i32 %tmp1.i.i, %tmp3.i.i        ; <i32> [#uses=3]
+  %tmp5.i.i = add i32 %tmp4.i.i, 17               ; <i32> [#uses=1]
+  %tmp8.i.i = zext i32 %tmp5.i.i to i64           ; <i64> [#uses=1]
+  %tmp.i20.i.i = tail call noalias i8* @malloc(i64 %tmp8.i.i) nounwind ; <i8*> [#uses=7]
+  %tmp10.i.i = bitcast i8* %tmp.i20.i.i to %"struct.llvm::StringMapEntry<void*>"* ; <%"struct.llvm::StringMapEntry<void*>"*> [#uses=2]
+  %tmp12.i.i = icmp eq i8* %tmp.i20.i.i, null     ; <i1> [#uses=1]
+  br i1 %tmp12.i.i, label %_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i, label %bb.i.i
+
+bb.i.i:                                           ; preds = %bb4.i
+  %tmp.i.i.i.i = bitcast i8* %tmp.i20.i.i to i32* ; <i32*> [#uses=1]
+  store i32 %tmp4.i.i, i32* %tmp.i.i.i.i, align 4
+  %tmp1.i19.i.i = getelementptr inbounds i8* %tmp.i20.i.i, i64 8 ; <i8*> [#uses=1]
+  %0 = bitcast i8* %tmp1.i19.i.i to i8**          ; <i8**> [#uses=1]
+  store i8* null, i8** %0, align 8
+  br label %_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i
+
+_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i: ; preds = %bb4.i, %bb.i.i
+  %tmp.i18.i.i = getelementptr inbounds i8* %tmp.i20.i.i, i64 16 ; <i8*> [#uses=1]
+  %tmp15.i.i = zext i32 %tmp4.i.i to i64          ; <i64> [#uses=2]
+  tail call void @llvm.memcpy.i64(i8* %tmp.i18.i.i, i8* %tmp41.i, i64 %tmp15.i.i, i32 1) nounwind
+  %tmp.i18.sum.i.i = add i64 %tmp15.i.i, 16       ; <i64> [#uses=1]
+  %tmp17.i.i = getelementptr inbounds i8* %tmp.i20.i.i, i64 %tmp.i18.sum.i.i ; <i8*> [#uses=1]
+  store i8 0, i8* %tmp17.i.i, align 1
+  %tmp.i.i.i = getelementptr inbounds i8* %tmp.i20.i.i, i64 8 ; <i8*> [#uses=1]
+  %1 = bitcast i8* %tmp.i.i.i to i8**             ; <i8**> [#uses=1]
+  store i8* null, i8** %1, align 8
+  %tmp22.i = load %"struct.llvm::StringMapEntryBase"** %tmp7.i, align 8 ; <%"struct.llvm::StringMapEntryBase"*> [#uses=1]
+  %tmp24.i = icmp eq %"struct.llvm::StringMapEntryBase"* %tmp22.i, inttoptr (i64 -1 to %"struct.llvm::StringMapEntryBase"*) ; <i1> [#uses=1]
+  br i1 %tmp24.i, label %bb9.i, label %_ZN4llvm9StringMapIPvNS_15MallocAllocatorEE16GetOrCreateValueIS1_EERNS_14StringMapEntryIS1_EENS_9StringRefET_.exit
+
+bb6.i:                                            ; preds = %entry
+  %tmp16.i = bitcast %"struct.llvm::StringMapEntryBase"* %tmp8.i to %"struct.llvm::StringMapEntry<void*>"* ; <%"struct.llvm::StringMapEntry<void*>"*> [#uses=1]
+  ret %"struct.llvm::StringMapEntry<void*>"* %tmp16.i
+
+bb9.i:                                            ; preds = %_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i
+  %tmp25.i = getelementptr inbounds %"struct.llvm::StringMap<void*,llvm::MallocAllocator>"* %this, i64 0, i32 0, i32 3 ; <i32*> [#uses=2]
+  %tmp26.i = load i32* %tmp25.i, align 8          ; <i32> [#uses=1]
+  %tmp27.i = add i32 %tmp26.i, -1                 ; <i32> [#uses=1]
+  store i32 %tmp27.i, i32* %tmp25.i, align 8
+  ret %"struct.llvm::StringMapEntry<void*>"* %tmp10.i.i
+
+_ZN4llvm9StringMapIPvNS_15MallocAllocatorEE16GetOrCreateValueIS1_EERNS_14StringMapEntryIS1_EENS_9StringRefET_.exit: ; preds = %_ZN4llvm14StringMapEntryIPvE6CreateINS_15MallocAllocatorES1_EEPS2_PKcS7_RT_T0_.exit.i
+  ret %"struct.llvm::StringMapEntry<void*>"* %tmp10.i.i
+}