Really really bad local register allocator bug. On X86, it was never using ESI, EDI...

it checks if ESI is available, it then looks at registers aliases to ESI. SIL is marked -2 (not allocatable) but isPhysRegAvailable() incorrectly assumes it is in use and returns false for ESI.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47499 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp
index 8f1cce6f4fb96dcdcd36ef511fa9de1ff3401377..99fc6c9028ab7ba4a6d9b3e55c8af02570ba3e2e 100644 (file)
--- a/lib/CodeGen/RegAllocLocal.cpp
+++ b/lib/CodeGen/RegAllocLocal.cpp
@@ -368,7 +368,7 @@ bool RALocal::isPhysRegAvailable(unsigned PhysReg) const {
   // not free!
   for (const unsigned *AliasSet = TRI->getAliasSet(PhysReg);
        *AliasSet; ++AliasSet)
-    if (PhysRegsUsed[*AliasSet] != -1) // Aliased register in use?
+    if (PhysRegsUsed[*AliasSet] >= 0) // Aliased register in use?
       return false;                    // Can't use this reg then.
   return true;
 }