Merge pull request #16235 from CarolEidt/FixPrefetchBuildBreak

Disable prefetch instructions for LEGACY_BACKEND

2 files changed, 12 insertions, 3 deletions

diff --git a/src/jit/emitxarch.cpp b/src/jit/emitxarch.cpp
index 2ae99e8edf..55c50360e3 100644
--- a/src/jit/emitxarch.cpp
+++ b/src/jit/emitxarch.cpp
@@ -2029,9 +2029,9 @@ UNATIVE_OFFSET emitter::emitInsSizeAM(instrDesc* id, code_t code)
 
         assert((attrSize == EA_4BYTE) || (attrSize == EA_PTRSIZE)    // Only for x64
                || (attrSize == EA_16BYTE) || (attrSize == EA_32BYTE) // only for x64
-               || (ins == INS_movzx) || (ins == INS_movsx) || (ins == INS_prefetcht0) ||
-               (ins == INS_prefetcht1)                                  // the prefetch instructions are always 3 bytes
-               || (ins == INS_prefetcht2) || (ins == INS_prefetchnta)); // and have part of their modr/m byte hardcoded
+               || (ins == INS_movzx) || (ins == INS_movsx)
+               // The prefetch instructions are always 3 bytes and have part of their modr/m byte hardcoded
+               || isPrefetch(ins));
         size = 3;
     }
     else
diff --git a/src/jit/emitxarch.h b/src/jit/emitxarch.h
index 395934ed5f..2fb1dd1bc2 100644
--- a/src/jit/emitxarch.h
+++ b/src/jit/emitxarch.h
@@ -192,6 +192,10 @@ bool isSse41Blendv(instruction ins)
 {
     return ins == INS_blendvps || ins == INS_blendvpd || ins == INS_pblendvb;
 }
+bool isPrefetch(instruction ins)
+{
+    return (ins == INS_prefetcht0) || (ins == INS_prefetcht1) || (ins == INS_prefetcht2) || (ins == INS_prefetchnta);
+}
 #else  // LEGACY_BACKEND
 bool UseVEXEncoding()
 {
@@ -246,6 +250,11 @@ bool TakesVexPrefix(instruction ins)
 {
     return false;
 }
+bool isPrefetch(instruction ins)
+{
+    return false;
+}
+
 code_t AddVexPrefixIfNeeded(instruction ins, code_t code, emitAttr attr)
 {
     return code;