From 11c9a50611fb83bdc71d6f25f3cbb372317a2cdc Mon Sep 17 00:00:00 2001 From: Adam Nemet Date: Fri, 11 Jul 2014 05:23:25 +0000 Subject: [PATCH] [X86] AVX512: Improve readability of isCDisp8 No functional change. As I was trying to understand this function, I found that variables were reused with confusing names and the broadcast case was a bit too implicit. Hopefully, this is an improvement. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212795 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp b/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp index dbd357cb008..7c30fc25ae0 100644 --- a/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp +++ b/lib/Target/X86/MCTargetDesc/X86MCCodeEmitter.cpp @@ -197,14 +197,23 @@ static bool isCDisp8(uint64_t TSFlags, int Value, int& CValue) { return isDisp8(Value); } - unsigned MemObjSize = 1U << CD8E; + unsigned ElemSize = 1U << CD8E; + unsigned MemObjSize; + // The unit of displacement is either + // - the size of a power-of-two number of elements or + // - the size of a single element for broadcasts or + // - the total vector size divided by a power-of-two number. if (CD8V & 4) { // Fixed vector length - MemObjSize *= 1U << (CD8V & 0x3); + unsigned NumElems = 1U << (CD8V & 0x3); + MemObjSize = ElemSize * NumElems; } else { // Modified vector length bool EVEX_b = (TSFlags >> X86II::VEXShift) & X86II::EVEX_B; - if (!EVEX_b) { + if (EVEX_b) + // Broadcast implies element size units. + MemObjSize = ElemSize; + else { unsigned EVEX_LL = ((TSFlags >> X86II::VEXShift) & X86II::VEX_L) ? 1 : 0; EVEX_LL += ((TSFlags >> X86II::VEXShift) & X86II::EVEX_L2) ? 2 : 0; assert(EVEX_LL < 3 && "");