GVN-hoist: fix early exit logic

The patch splits a complex && if condition into easier to read and understand
logic.  That wrong early exit condition was letting some instructions with not
all operands available pass through when HoistingGeps was true.

Differential Revision: https://reviews.llvm.org/D23174

llvm-svn: 277785

1 files changed, 11 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/Scalar/GVNHoist.cpp b/llvm/lib/Transforms/Scalar/GVNHoist.cpp
index 171a8edfee4..c734dfced8e 100644
--- a/llvm/lib/Transforms/Scalar/GVNHoist.cpp
+++ b/llvm/lib/Transforms/Scalar/GVNHoist.cpp
@@ -750,12 +750,19 @@ private:
         Repl = InstructionsToHoist.front();
 
         // We can move Repl in HoistPt only when all operands are available.
-        // When not HoistingGeps we need to copy the GEPs now.
         // The order in which hoistings are done may influence the availability
         // of operands.
-        if (!allOperandsAvailable(Repl, HoistPt) && !HoistingGeps &&
-            !makeGepOperandsAvailable(Repl, HoistPt, InstructionsToHoist))
-          continue;
+        if (!allOperandsAvailable(Repl, HoistPt)) {
+
+          // When HoistingGeps there is nothing more we can do to make the
+          // operands available: just continue.
+          if (HoistingGeps)
+            continue;
+
+          // When not HoistingGeps we need to copy the GEPs.
+          if (!makeGepOperandsAvailable(Repl, HoistPt, InstructionsToHoist))
+            continue;
+        }
 
         // Move the instruction at the end of HoistPt.
         Instruction *Last = HoistPt->getTerminator();