Fix sanity-checking in 'maskUnsigned' code to be more precise:
use or def-and-use operands can be substituted after one def-only
operand has been substituted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7674 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/SparcV9/SparcV9InstrSelection.cpp b/lib/Target/SparcV9/SparcV9InstrSelection.cpp
index b55bd48..1654c55 100644
--- a/lib/Target/SparcV9/SparcV9InstrSelection.cpp
+++ b/lib/Target/SparcV9/SparcV9InstrSelection.cpp
@@ -2859,9 +2859,19 @@
unsigned numSubst = 0;
for (unsigned i=0, N=mvec.size(); i < N; ++i) {
+
+ // Make sure we substitute all occurrences of dest in these instrs.
+ // Otherwise, we will have bogus code.
bool someArgsWereIgnored = false;
- numSubst += mvec[i]->substituteValue(dest, tmpI, /*defsOnly*/ true,
- /*defsAndUses*/ false,
+
+ // Make sure not to substitute an upwards-exposed use -- that would
+ // introduce a use of `tmpI' with no preceding def. Therefore,
+ // substitute a use or def-and-use operand only if a previous def
+ // operand has already been substituted (i.e., numSusbt > 0).
+ //
+ numSubst += mvec[i]->substituteValue(dest, tmpI,
+ /*defsOnly*/ numSubst == 0,
+ /*notDefsAndUses*/ numSubst > 0,
someArgsWereIgnored);
assert(!someArgsWereIgnored &&
"Operand `dest' exists but not replaced: probably bogus!");