From: Guozhi Wei <carrot@google.com>
Date: Tue, 10 Oct 2017 20:31:27 +0000 (+0000)
Subject: [CGExprScalar] In EmitCompare trunc the result if it has different type as E->getType()
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=6d6c393741c7982249c1333cdc9392d45764cdd5;p=clang

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

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.

Differential Revision: https://reviews.llvm.org/D38656



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@315358 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index fba9574b02..68a2f13e70 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -3214,6 +3214,16 @@ Value *ScalarExprEmitter::EmitCompare(const BinaryOperator *E,
       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 = 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());
     }
diff --git a/test/CodeGen/ppc-vector-compare.cc b/test/CodeGen/ppc-vector-compare.cc
new file mode 100644
index 0000000000..43fbf84c6d
--- /dev/null
+++ b/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;
+}
+