Some reassociate optimizations create new instructions, which they insert just

before the expression root.  Any existing operators that are changed to use one
of them needs to be moved between it and the expression root, and recursively
for the operators using that one.  When I rewrote RewriteExprTree I accidentally
inverted the logic, resulting in the compacting going down from operators to
operands rather than up from operands to the operators using them, oops.  Fix
this, resolving PR12963.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159265 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 0 deletions

diff --git a/test/Transforms/Reassociate/crash.ll b/test/Transforms/Reassociate/crash.ll
index e2ebcdd..a99c844 100644
--- a/test/Transforms/Reassociate/crash.ll
+++ b/test/Transforms/Reassociate/crash.ll
@@ -119,3 +119,17 @@ for.cond:                                         ; preds = %for.cond, %entry
   %conv = zext i16 %p to i32
   br label %for.cond
 }
+
+; PR12963
+@a = external global i8
+define i8 @f0(i8 %x) {
+  %t0 = load i8* @a
+  %t1 = mul i8 %x, %x
+  %t2 = mul i8 %t1, %t1
+  %t3 = mul i8 %t2, %t2
+  %t4 = mul i8 %t3, %x
+  %t5 = mul i8 %t4, %t4
+  %t6 = mul i8 %t5, %x
+  %t7 = mul i8 %t6, %t0
+  ret i8 %t7
+}