diff options
author | Chris Lattner <sabre@nondot.org> | 2012-06-01 05:29:15 +0000 |
---|---|---|
committer | Chris Lattner <sabre@nondot.org> | 2012-06-01 05:29:15 +0000 |
commit | f59e4e34528a078c2db57ee72b2814b495989124 (patch) | |
tree | 8a31b5a8b9cc32c3a37bd94c6c191af5d511eb95 | |
parent | d9567223e852c48b4022345ed130000810521438 (diff) | |
download | llvm-f59e4e34528a078c2db57ee72b2814b495989124.tar.gz llvm-f59e4e34528a078c2db57ee72b2814b495989124.tar.bz2 llvm-f59e4e34528a078c2db57ee72b2814b495989124.tar.xz |
enhance the logic for looking through tailcalls to look through transparent casts
in multiple-return value scenarios, like what happens on X86-64 when returning
small structs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157800 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/CodeGen/Analysis.cpp | 22 | ||||
-rw-r--r-- | test/CodeGen/X86/tailcall-64.ll | 46 |
2 files changed, 67 insertions, 1 deletions
diff --git a/lib/CodeGen/Analysis.cpp b/lib/CodeGen/Analysis.cpp index dd11d15975..1a8968dd28 100644 --- a/lib/CodeGen/Analysis.cpp +++ b/lib/CodeGen/Analysis.cpp @@ -322,7 +322,27 @@ bool llvm::isInTailCallPosition(ImmutableCallSite CS, Attributes CalleeRetAttr, return false; // Otherwise, make sure the unmodified return value of I is the return value. - return getNoopInput(Ret->getOperand(0), TLI) == I; + // We handle two cases: multiple return values + scalars. + Value *RetVal = Ret->getOperand(0); + if (!isa<InsertValueInst>(RetVal) || !isa<StructType>(RetVal->getType())) + // Handle scalars first. + return getNoopInput(Ret->getOperand(0), TLI) == I; + + // If this is an aggregate return, look through the insert/extract values and + // see if each is transparent. + for (unsigned i = 0, e =cast<StructType>(RetVal->getType())->getNumElements(); + i != e; ++i) { + const Value *InScalar = getNoopInput(FindInsertedValue(RetVal, i), TLI); + + // If the scalar value being inserted is an extractvalue of the right index + // from the call, then everything is good. + const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(InScalar); + if (EVI == 0 || EVI->getOperand(0) != I || EVI->getNumIndices() != 1 || + EVI->getIndices()[0] != i) + return false; + } + + return true; } bool llvm::isInTailCallPosition(SelectionDAG &DAG, SDNode *Node, diff --git a/test/CodeGen/X86/tailcall-64.ll b/test/CodeGen/X86/tailcall-64.ll index a3ef2dc8ef..98e728c909 100644 --- a/test/CodeGen/X86/tailcall-64.ll +++ b/test/CodeGen/X86/tailcall-64.ll @@ -41,3 +41,49 @@ define <4 x i32> @test_vectorbitcast() { } ; CHECK: test_vectorbitcast: ; CHECK: jmp _testv ## TAILCALL + + +declare { i64, i64 } @testp() + +define {i64, i64} @test_pair_trivial() { + %A = tail call { i64, i64} @testp() + ret { i64, i64} %A +} +; CHECK: test_pair_trivial: +; CHECK: jmp _testp ## TAILCALL + + + +define {i64, i64} @test_pair_trivial_extract() { + %A = tail call { i64, i64} @testp() + %x = extractvalue { i64, i64} %A, 0 + %y = extractvalue { i64, i64} %A, 1 + + %b = insertvalue {i64, i64} undef, i64 %x, 0 + %c = insertvalue {i64, i64} %b, i64 %y, 1 + + ret { i64, i64} %c +} + +; CHECK: test_pair_trivial_extract: +; CHECK: jmp _testp ## TAILCALL + +define {i8*, i64} @test_pair_conv_extract() { + %A = tail call { i64, i64} @testp() + %x = extractvalue { i64, i64} %A, 0 + %y = extractvalue { i64, i64} %A, 1 + + %x1 = inttoptr i64 %x to i8* + + %b = insertvalue {i8*, i64} undef, i8* %x1, 0 + %c = insertvalue {i8*, i64} %b, i64 %y, 1 + + ret { i8*, i64} %c +} + +; CHECK: test_pair_conv_extract: +; CHECK: jmp _testp ## TAILCALL + + + + |