[PATCH] D63967: Handle IntToPtr in isBytewiseValue

[Vitaly Buka via Phabricator via cfe-commits]

vitalybuka created this revision.
Herald added subscribers: llvm-commits, cfe-commits, hiraditya.
Herald added projects: clang, LLVM.

This helps with more efficient use of memset for pattern initialization


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D63967

Files:
  clang/test/CodeGenCXX/auto-var-init.cpp
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/unittests/Analysis/ValueTrackingTest.cpp


Index: llvm/unittests/Analysis/ValueTrackingTest.cpp
===================================================================
--- llvm/unittests/Analysis/ValueTrackingTest.cpp
+++ llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -782,11 +782,11 @@
         "i16* inttoptr (i64 0 to i16*)",
     },
     {
-        "",
+        "i8 -1",
         "i16* inttoptr (i64 -1 to i16*)",
     },
     {
-        "",
+        "i8 -86",
         "i16* inttoptr (i64 -6148914691236517206 to i16*)",
     },
     {
@@ -794,7 +794,7 @@
         "i16* inttoptr (i48 -1 to i16*)",
     },
     {
-        "",
+        "i8 -1",
         "i16* inttoptr (i96 -1 to i16*)",
     },
     {
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -3219,6 +3219,17 @@
     }
   }
 
+  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;
Index: clang/test/CodeGenCXX/auto-var-init.cpp
===================================================================
--- clang/test/CodeGenCXX/auto-var-init.cpp
+++ clang/test/CodeGenCXX/auto-var-init.cpp
@@ -1032,14 +1032,8 @@
 // CHECK:            %uninit = alloca [4 x i32*], align
 // CHECK-NEXT:       call void @{{.*}}used{{.*}}%uninit)
 // PATTERN-O1-LABEL: @test_intptr4_uninit()
-// PATTERN-O1:       %1 = getelementptr inbounds [4 x i32*], [4 x i32*]* %uninit, i64 0, i64 0
-// PATTERN-O1-NEXT:  store i32* inttoptr (i64 -6148914691236517206 to i32*), i32** %1, align 16
-// PATTERN-O1-NEXT:  %2 = getelementptr inbounds [4 x i32*], [4 x i32*]* %uninit, i64 0, i64 1
-// PATTERN-O1-NEXT:  store i32* inttoptr (i64 -6148914691236517206 to i32*), i32** %2, align 8
-// PATTERN-O1-NEXT:  %3 = getelementptr inbounds [4 x i32*], [4 x i32*]* %uninit, i64 0, i64 2
-// PATTERN-O1-NEXT:  store i32* inttoptr (i64 -6148914691236517206 to i32*), i32** %3, align 16
-// PATTERN-O1-NEXT:  %4 = getelementptr inbounds [4 x i32*], [4 x i32*]* %uninit, i64 0, i64 3
-// PATTERN-O1-NEXT:  store i32* inttoptr (i64 -6148914691236517206 to i32*), i32** %4, align 8
+// PATTERN-O1:       %1 = bitcast [4 x i32*]* %uninit to i8*
+// PATTERN-O1-NEXT:  call void @llvm.memset.p0i8.i64(i8* nonnull align 16 %1, i8 -86, i64 32, i1 false)
 // ZERO-LABEL:       @test_intptr4_uninit()
 // ZERO:             call void @llvm.memset{{.*}}, i8 0,
 


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