123 lines
5.4 KiB
Diff
123 lines
5.4 KiB
Diff
From b9d6dba608ab50d2e4a1b0f2318a5d1b390fc702 Mon Sep 17 00:00:00 2001
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From: Vedant Kumar <vsk@apple.com>
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Date: Tue, 18 Dec 2018 21:05:03 +0000
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Subject: [PATCH] [CodeGen] Handle mixed-width ops in mixed-sign
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mul-with-overflow lowering
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The special lowering for __builtin_mul_overflow introduced in r320902
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fixed an ICE seen when passing mixed-sign operands to the builtin.
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This patch extends the special lowering to cover mixed-width, mixed-sign
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operands. In a few common scenarios, calls to muloti4 will no longer be
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emitted.
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This should address the latest comments in PR34920 and work around the
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link failure seen in:
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https://bugzilla.redhat.com/show_bug.cgi?id=1657544
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Testing:
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- check-clang
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- A/B output comparison with: https://gist.github.com/vedantk/3eb9c88f82e5c32f2e590555b4af5081
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Differential Revision: https://reviews.llvm.org/D55843
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git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@349542 91177308-0d34-0410-b5e6-96231b3b80d8
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---
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lib/CodeGen/CGBuiltin.cpp | 19 ++++++++++++++-----
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test/CodeGen/builtins-overflow.c | 21 +++++++++++++++++++++
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2 files changed, 35 insertions(+), 5 deletions(-)
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diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
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index 0770c20..4303a7a 100644
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--- a/lib/CodeGen/CGBuiltin.cpp
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+++ b/lib/CodeGen/CGBuiltin.cpp
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@@ -1077,7 +1077,7 @@ static bool isSpecialMixedSignMultiply(unsigned BuiltinID,
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WidthAndSignedness Op2Info,
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WidthAndSignedness ResultInfo) {
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return BuiltinID == Builtin::BI__builtin_mul_overflow &&
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- Op1Info.Width == Op2Info.Width && Op1Info.Width >= ResultInfo.Width &&
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+ std::max(Op1Info.Width, Op2Info.Width) >= ResultInfo.Width &&
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Op1Info.Signed != Op2Info.Signed;
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}
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@@ -1098,11 +1098,20 @@ EmitCheckedMixedSignMultiply(CodeGenFunction &CGF, const clang::Expr *Op1,
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const clang::Expr *UnsignedOp = Op1Info.Signed ? Op2 : Op1;
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llvm::Value *Signed = CGF.EmitScalarExpr(SignedOp);
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llvm::Value *Unsigned = CGF.EmitScalarExpr(UnsignedOp);
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+ unsigned SignedOpWidth = Op1Info.Signed ? Op1Info.Width : Op2Info.Width;
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+ unsigned UnsignedOpWidth = Op1Info.Signed ? Op2Info.Width : Op1Info.Width;
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+
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+ // One of the operands may be smaller than the other. If so, [s|z]ext it.
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+ if (SignedOpWidth < UnsignedOpWidth)
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+ Signed = CGF.Builder.CreateSExt(Signed, Unsigned->getType(), "op.sext");
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+ if (UnsignedOpWidth < SignedOpWidth)
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+ Unsigned = CGF.Builder.CreateZExt(Unsigned, Signed->getType(), "op.zext");
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llvm::Type *OpTy = Signed->getType();
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llvm::Value *Zero = llvm::Constant::getNullValue(OpTy);
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Address ResultPtr = CGF.EmitPointerWithAlignment(ResultArg);
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llvm::Type *ResTy = ResultPtr.getElementType();
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+ unsigned OpWidth = std::max(Op1Info.Width, Op2Info.Width);
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// Take the absolute value of the signed operand.
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llvm::Value *IsNegative = CGF.Builder.CreateICmpSLT(Signed, Zero);
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@@ -1120,8 +1129,8 @@ EmitCheckedMixedSignMultiply(CodeGenFunction &CGF, const clang::Expr *Op1,
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if (ResultInfo.Signed) {
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// Signed overflow occurs if the result is greater than INT_MAX or lesser
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// than INT_MIN, i.e when |Result| > (INT_MAX + IsNegative).
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- auto IntMax = llvm::APInt::getSignedMaxValue(ResultInfo.Width)
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- .zextOrSelf(Op1Info.Width);
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+ auto IntMax =
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+ llvm::APInt::getSignedMaxValue(ResultInfo.Width).zextOrSelf(OpWidth);
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llvm::Value *MaxResult =
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CGF.Builder.CreateAdd(llvm::ConstantInt::get(OpTy, IntMax),
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CGF.Builder.CreateZExt(IsNegative, OpTy));
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@@ -1139,9 +1148,9 @@ EmitCheckedMixedSignMultiply(CodeGenFunction &CGF, const clang::Expr *Op1,
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llvm::Value *Underflow = CGF.Builder.CreateAnd(
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IsNegative, CGF.Builder.CreateIsNotNull(UnsignedResult));
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Overflow = CGF.Builder.CreateOr(UnsignedOverflow, Underflow);
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- if (ResultInfo.Width < Op1Info.Width) {
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+ if (ResultInfo.Width < OpWidth) {
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auto IntMax =
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- llvm::APInt::getMaxValue(ResultInfo.Width).zext(Op1Info.Width);
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+ llvm::APInt::getMaxValue(ResultInfo.Width).zext(OpWidth);
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llvm::Value *TruncOverflow = CGF.Builder.CreateICmpUGT(
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UnsignedResult, llvm::ConstantInt::get(OpTy, IntMax));
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Overflow = CGF.Builder.CreateOr(Overflow, TruncOverflow);
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diff --git a/test/CodeGen/builtins-overflow.c b/test/CodeGen/builtins-overflow.c
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index 57f90eb..79a3186 100644
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--- a/test/CodeGen/builtins-overflow.c
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+++ b/test/CodeGen/builtins-overflow.c
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@@ -339,6 +339,27 @@ long long test_smulll_overflow(long long x, long long y) {
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return result;
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}
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+int test_mixed_sign_mul_overflow_sext_signed_op(int x, unsigned long long y) {
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+// CHECK: @test_mixed_sign_mul_overflow_sext_signed_op
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+// CHECK: [[SignedOp:%.*]] = sext i32 %0 to i64
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+// CHECK: [[IsNeg:%.*]] = icmp slt i64 [[SignedOp]], 0
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+ int result;
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+ if (__builtin_mul_overflow(x, y, &result))
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+ return LongErrorCode;
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+ return result;
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+}
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+
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+int test_mixed_sign_mul_overflow_zext_unsigned_op(long long x, unsigned y) {
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+// CHECK: @test_mixed_sign_mul_overflow_zext_unsigned_op
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+// CHECK: [[UnsignedOp:%.*]] = zext i32 %1 to i64
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+// CHECK: [[IsNeg:%.*]] = icmp slt i64 %0, 0
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+// CHECK: @llvm.umul.with.overflow.i64({{.*}}, i64 [[UnsignedOp]])
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+ int result;
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+ if (__builtin_mul_overflow(x, y, &result))
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+ return LongErrorCode;
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+ return result;
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+}
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+
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int test_mixed_sign_mull_overflow(int x, unsigned y) {
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// CHECK: @test_mixed_sign_mull_overflow
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// CHECK: [[IsNeg:%.*]] = icmp slt i32 [[Op1:%.*]], 0
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--
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1.8.3.1
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