From f236bb1b5bea26acbcb39f8232e64c638904bc82 Mon Sep 17 00:00:00 2001 From: Ulrich Weigand Date: Thu, 3 Jul 2014 15:06:47 +0000 Subject: Fix ppcf128 component access on little-endian systems The PowerPC 128-bit long double data type (ppcf128 in LLVM) is in fact a pair of two doubles, where one is considered the "high" or more-significant part, and the other is considered the "low" or less-significant part. When a ppcf128 value is stored in memory or a register pair, the high part always comes first, i.e. at the lower memory address or in the lower-numbered register, and the low part always comes second. This is true both on big-endian and little-endian PowerPC systems. (Similar to how with a complex number, the real part always comes first and the imaginary part second, no matter the byte order of the system.) This was implemented incorrectly for little-endian systems in LLVM. This commit fixes three related issues: - When printing an immediate ppcf128 constant to assembler output in emitGlobalConstantFP, emit the high part first on both big- and little-endian systems. - When lowering a ppcf128 type to a pair of f64 types in SelectionDAG (which is used e.g. when generating code to load an argument into a register pair), use correct low/high part ordering on little-endian systems. - In a related issue, because lowering ppcf128 into a pair of f64 must operate differently from lowering an int128 into a pair of i64, bitcasts between ppcf128 and int128 must not be optimized away by the DAG combiner on little-endian systems, but must effect a word-swap. Reviewed by Hal Finkel. llvm-svn: 212274 --- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp') diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 249683f0201..28d8e984349 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -169,7 +169,7 @@ static SDValue getCopyFromParts(SelectionDAG &DAG, SDLoc DL, SDValue Lo, Hi; Lo = DAG.getNode(ISD::BITCAST, DL, EVT(MVT::f64), Parts[0]); Hi = DAG.getNode(ISD::BITCAST, DL, EVT(MVT::f64), Parts[1]); - if (TLI.isBigEndian()) + if (TLI.hasBigEndianPartOrdering(ValueVT)) std::swap(Lo, Hi); Val = DAG.getNode(ISD::BUILD_PAIR, DL, ValueVT, Lo, Hi); } else { -- cgit v1.2.3