diff options
| -rw-r--r-- | lib/Transforms/Scalar/MemCpyOptimizer.cpp | 8 | ||||
| -rw-r--r-- | test/Transforms/MemCpyOpt/crash.ll | 19 |
2 files changed, 24 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp index 318e212899..6f93e326ba 100644 --- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp +++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp @@ -675,6 +675,14 @@ bool MemCpyOpt::processMemCpyMemCpyDependence(MemCpyInst *M, MemCpyInst *MDep, if (M->getSource() != MDep->getDest() || MDep->isVolatile()) return false; + // If dep instruction is reading from our current input, then it is a noop + // transfer and substituting the input won't change this instruction. Just + // ignore the input and let someone else zap MDep. This handles cases like: + // memcpy(a <- a) + // memcpy(b <- a) + if (M->getSource() == MDep->getSource()) + return false; + // Second, the length of the memcpy's must be the same, or the preceeding one // must be larger than the following one. ConstantInt *C1 = dyn_cast<ConstantInt>(MDep->getLength()); diff --git a/test/Transforms/MemCpyOpt/crash.ll b/test/Transforms/MemCpyOpt/crash.ll index bf5b234675..cc3a6b0527 100644 --- a/test/Transforms/MemCpyOpt/crash.ll +++ b/test/Transforms/MemCpyOpt/crash.ll @@ -1,5 +1,4 @@ -; RUN: opt < %s -memcpyopt -disable-output -; PR4882 +; RUN: opt < %s -basicaa -memcpyopt -disable-output target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64" target triple = "armv7-eabi" @@ -7,7 +6,8 @@ target triple = "armv7-eabi" %struct.qw = type { [4 x float] } %struct.bar = type { %struct.qw, %struct.qw, %struct.qw, %struct.qw, %struct.qw, float, float} -define arm_aapcs_vfpcc void @test1(%struct.bar* %this) { +; PR4882 +define void @test1(%struct.bar* %this) { entry: %0 = getelementptr inbounds %struct.bar* %this, i32 0, i32 0, i32 0, i32 0 store float 0.000000e+00, float* %0, align 4 @@ -43,3 +43,16 @@ entry: store float 0.000000e+00, float* %15, align 4 unreachable } + +; PR8753 + +declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32, +i1) nounwind + +define void @test2(i32 %cmd) nounwind { + call void @llvm.memcpy.p0i8.p0i8.i64(i8* undef, i8* undef, i64 20, i32 1, i1 +false) nounwind + call void @llvm.memcpy.p0i8.p0i8.i64(i8* null, i8* undef, i64 20, i32 1, i1 +false) nounwind + ret void +} |