[PATCH] D38656: [CGExprScalar] In EmitCompare trunc the result if it has different type as E->getType()

[Guozhi Wei via Phabricator via cfe-commits]

Carrot created this revision.
Herald added a subscriber: nemanjai.

Usually compare expression should return i1 type, so EmitScalarConversion is called before return

  return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(), E->getExprLoc());

But when ppc intrinsic is called to compare vectors, the ppc intrinsic can return i32 even E->getType() is BoolTy, in this case EmitScalarConversion does nothing, an i32 type result is returned and causes crash later.

This patch detects this case and truncates the result before return.


https://reviews.llvm.org/D38656

Files:
  lib/CodeGen/CGExprScalar.cpp
  test/CodeGen/ppc-vector-compare.cc


Index: test/CodeGen/ppc-vector-compare.cc
===================================================================
--- test/CodeGen/ppc-vector-compare.cc
+++ test/CodeGen/ppc-vector-compare.cc
@@ -0,0 +1,11 @@
+// RUN: %clang_cc1 -target-feature +altivec -triple powerpc64-unknown-unknown -emit-llvm %s \
+// RUN:            -o - | FileCheck %s
+
+#include <altivec.h>
+
+// CHECK-LABEL: @_Z5test1Dv8_tS_
+// CHECK: @llvm.ppc.altivec.vcmpequh.p
+bool test1(vector unsigned short v1, vector unsigned short v2) {
+  return v1 == v2;
+}
+
Index: lib/CodeGen/CGExprScalar.cpp
===================================================================
--- lib/CodeGen/CGExprScalar.cpp
+++ lib/CodeGen/CGExprScalar.cpp
@@ -3214,6 +3214,17 @@
       Value *CR6Param = Builder.getInt32(CR6);
       llvm::Function *F = CGF.CGM.getIntrinsic(ID);
       Result = Builder.CreateCall(F, {CR6Param, FirstVecArg, SecondVecArg});
+
+      // The result type of intrinsic may not be same as E->getType().
+      // If E->getType() is not BoolTy, EmitScalarConversion will do the
+      // conversion work. If E->getType() is BoolTy, EmitScalarConversion will
+      // do nothing, if ResultTy is not i1 at the same time, it will cause
+      // crash later.
+      llvm::IntegerType *ResultTy =
+                         dyn_cast<llvm::IntegerType>(Result->getType());
+      if ((ResultTy->getBitWidth() > 1) &&
+          (E->getType() == CGF.getContext().BoolTy))
+        Result = Builder.CreateTrunc(Result, Builder.getInt1Ty());
       return EmitScalarConversion(Result, CGF.getContext().BoolTy, E->getType(),
                                   E->getExprLoc());
     }


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