Handle IntToPtr in isBytewiseValue

Summary:
This helps with more efficient use of memset for pattern initialization

From @pcc prototype for -ftrivial-auto-var-init=pattern optimizations

Binary size change on CTMark, (with -fuse-ld=lld -Wl,--icf=all, similar results with default linker options)
```
                   master           patch      diff
Os           8.238864e+05    8.238864e+05       0.0
O3           1.054797e+06    1.054797e+06       0.0
Os zero      8.292384e+05    8.292384e+05       0.0
O3 zero      1.062626e+06    1.062626e+06       0.0
Os pattern   8.579712e+05    8.338048e+05 -0.030299
O3 pattern   1.090502e+06    1.067574e+06 -0.020481
```

Zero vs Pattern on master
```
               zero       pattern      diff
Os     8.292384e+05  8.579712e+05  0.036578
O3     1.062626e+06  1.090502e+06  0.025124
```

Zero vs Pattern with the patch
```
               zero       pattern      diff
Os     8.292384e+05  8.338048e+05  0.003333
O3     1.062626e+06  1.067574e+06  0.003193
```

Reviewers: pcc, eugenis

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D63967

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365858 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp
index 27d8e324fad21662e365a14a1451cca60c5bf13c..6857cf412edd0bc26fe1706094ed5002edc5e7ef 100644 (file)
--- a/lib/Analysis/ValueTracking.cpp
+++ b/lib/Analysis/ValueTracking.cpp
@@ -3218,6 +3218,17 @@ Value *llvm::isBytewiseValue(Value *V, const DataLayout &DL) {
     }
   }
 
+  if (auto *CE = dyn_cast<ConstantExpr>(C)) {
+    if (CE->getOpcode() == Instruction::IntToPtr) {
+      auto PS = DL.getPointerSizeInBits(
+          cast<PointerType>(CE->getType())->getAddressSpace());
+      return isBytewiseValue(
+          ConstantExpr::getIntegerCast(CE->getOperand(0),
+                                       Type::getIntNTy(Ctx, PS), false),
+          DL);
+    }
+  }
+
   auto Merge = [&](Value *LHS, Value *RHS) -> Value * {
     if (LHS == RHS)
       return LHS;

diff --git a/unittests/Analysis/ValueTrackingTest.cpp b/unittests/Analysis/ValueTrackingTest.cpp
index 90c879d281264e4fcfdb02fcc2c1044eed795b2a..9f486e85759ac2097cedd8598223bca302927134 100644 (file)
--- a/unittests/Analysis/ValueTrackingTest.cpp
+++ b/unittests/Analysis/ValueTrackingTest.cpp
@@ -794,11 +794,11 @@ const std::pair<const char *, const char *> IsBytewiseValueTests[] = {
         "i16* inttoptr (i64 0 to i16*)",
     },
     {
-        "",
+        "i8 -1",
         "i16* inttoptr (i64 -1 to i16*)",
     },
     {
-        "",
+        "i8 -86",
         "i16* inttoptr (i64 -6148914691236517206 to i16*)",
     },
     {
@@ -806,7 +806,7 @@ const std::pair<const char *, const char *> IsBytewiseValueTests[] = {
         "i16* inttoptr (i48 -1 to i16*)",
     },
     {
-        "",
+        "i8 -1",
         "i16* inttoptr (i96 -1 to i16*)",
     },
     {