[llvm] e6ce0dc - [StackSafety,NFC] Extract addOverflowNever

[Vitaly Buka via llvm-commits]

Author: Vitaly Buka
Date: 2020-06-12T17:42:32-07:00
New Revision: e6ce0dc5de37a51afed255c7e384d2016924dbbb

URL: https://github.com/llvm/llvm-project/commit/e6ce0dc5de37a51afed255c7e384d2016924dbbb
DIFF: https://github.com/llvm/llvm-project/commit/e6ce0dc5de37a51afed255c7e384d2016924dbbb.diff

LOG: [StackSafety,NFC] Extract addOverflowNever

Added: 
    

Modified: 
    llvm/lib/Analysis/StackSafetyAnalysis.cpp
    llvm/test/Analysis/StackSafetyAnalysis/local.ll
    llvm/test/Analysis/StackSafetyAnalysis/memintrin.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/StackSafetyAnalysis.cpp b/llvm/lib/Analysis/StackSafetyAnalysis.cpp
index 853707e9c23d..3fb5c294acf6 100644
--- a/llvm/lib/Analysis/StackSafetyAnalysis.cpp
+++ b/llvm/lib/Analysis/StackSafetyAnalysis.cpp
@@ -98,6 +98,13 @@ bool isUnsafe(const ConstantRange &R) {
   return R.isEmptySet() || R.isFullSet() || R.isUpperSignWrapped();
 }
 
+ConstantRange addOverflowNever(const ConstantRange &L, const ConstantRange &R) {
+  if (L.signedAddMayOverflow(R) !=
+      ConstantRange::OverflowResult::NeverOverflows)
+    return ConstantRange(L.getBitWidth(), true);
+  return L.add(R);
+}
+
 /// Calculate the allocation size of a given alloca. Returns empty range
 // in case of confution.
 ConstantRange getStaticAllocaSizeRange(const AllocaInst &AI) {
@@ -237,10 +244,7 @@ StackSafetyLocalAnalysis::getAccessRange(Value *Addr, Value *Base,
   if (isUnsafe(Offsets))
     return UnknownRange;
 
-  if (Offsets.signedAddMayOverflow(SizeRange) !=
-      ConstantRange::OverflowResult::NeverOverflows)
-    return UnknownRange;
-  Offsets = Offsets.add(SizeRange);
+  Offsets = addOverflowNever(Offsets, SizeRange);
   if (isUnsafe(Offsets))
     return UnknownRange;
   return Offsets;
@@ -453,10 +457,7 @@ ConstantRange StackSafetyDataFlowAnalysis<CalleeTy>::getArgumentAccessRange(
     return Access;
   if (Access.isFullSet())
     return UnknownRange;
-  if (Offsets.signedAddMayOverflow(Access) !=
-      ConstantRange::OverflowResult::NeverOverflows)
-    return UnknownRange;
-  return Access.add(Offsets);
+  return addOverflowNever(Access, Offsets);
 }
 
 template <typename CalleeTy>

diff  --git a/llvm/test/Analysis/StackSafetyAnalysis/local.ll b/llvm/test/Analysis/StackSafetyAnalysis/local.ll
index 75cf64fb1777..e0f450a975ab 100644
--- a/llvm/test/Analysis/StackSafetyAnalysis/local.ll
+++ b/llvm/test/Analysis/StackSafetyAnalysis/local.ll
@@ -459,4 +459,29 @@ entry:
   %z3 = bitcast i8* %z2 to [100000 x i64]*
   call void @ByValArray([100000 x i64]* byval %z3)
   ret void
+}
+
+define dso_local i8 @LoadMinInt64(i8* %p) {
+  ; CHECK-LABEL: @LoadMinInt64{{$}}
+  ; CHECK-NEXT: args uses:
+  ; CHECK-NEXT: p[]: [-9223372036854775808,-9223372036854775807){{$}}
+  ; CHECK-NEXT: allocas uses:
+  ; CHECK-NOT: ]:
+  %p2 = getelementptr i8, i8* %p, i64 -9223372036854775808
+  %v = load i8, i8* %p2, align 1
+  ret i8 %v
+}
+
+define void @Overflow() {
+; CHECK-LABEL: @Overflow dso_preemptable{{$}}
+; CHECK-NEXT: args uses:
+; CHECK-NEXT: allocas uses:
+; LOCAL: x[1]: empty-set, @LoadMinInt64(arg0, [-9223372036854775808,-9223372036854775807)){{$}}
+; GLOBAL: x[1]: full-set, @LoadMinInt64(arg0, [-9223372036854775808,-9223372036854775807)){{$}}
+; CHECK-NOT: ]:
+entry:
+  %x = alloca i8, align 4
+  %x2 = getelementptr i8, i8* %x, i64 -9223372036854775808
+  %v = call i8 @LoadMinInt64(i8* %x2)
+  ret void
 }
\ No newline at end of file

diff  --git a/llvm/test/Analysis/StackSafetyAnalysis/memintrin.ll b/llvm/test/Analysis/StackSafetyAnalysis/memintrin.ll
index 4d55de5b631a..70135a3a1875 100644
--- a/llvm/test/Analysis/StackSafetyAnalysis/memintrin.ll
+++ b/llvm/test/Analysis/StackSafetyAnalysis/memintrin.ll
@@ -6,6 +6,7 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
+declare void @llvm.memset.p0i8.i64(i8* %dest, i8 %val, i64 %len, i1 %isvolatile)
 declare void @llvm.memset.p0i8.i32(i8* %dest, i8 %val, i32 %len, i1 %isvolatile)
 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 %len, i1 %isvolatile)
 declare void @llvm.memmove.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 %len, i1 %isvolatile)