Restructure ArgumentPromotion a bit. Instead of just having a single boolean

that says "unconditional loads from this argument are safe", we now keep track
of the safety per set of indices from which loads happen. This prevents
ArgPromotion from promoting loads that aren't really valid. As an added effect,
this will now disregard the the type of the indices passed to a GEP, so
"load GEP %A, i32 1" and "load GEP %A, i64 1" will result in a single argument,
not two.

This fixes PR2598, for which a testcase has been added as well.

llvm-svn: 54159

1 files changed, 25 insertions, 0 deletions

diff --git a/llvm/test/Transforms/ArgumentPromotion/2008-07-02-array-indexing.ll b/llvm/test/Transforms/ArgumentPromotion/2008-07-02-array-indexing.ll
new file mode 100644
index 00000000000..11bcb285d5e
--- /dev/null
+++ b/llvm/test/Transforms/ArgumentPromotion/2008-07-02-array-indexing.ll
@@ -0,0 +1,25 @@
+; RUN: llvm-as < %s | opt -argpromotion | llvm-dis > %t
+; RUN: cat %t | grep {define.*@callee(.*i32\\*}
+; PR2498
+
+; This test tries to convince argpromotion about promoting the load from %A + 2,
+; because there is a load of %A in the entry block
+define internal i32 @callee(i1 %C, i32* %A) {
+entry:
+        ; Unconditonally load the element at %A
+        %A.0 = load i32* %A
+        br i1 %C, label %T, label %F
+T:
+        ret i32 %A.0
+F:
+        ; Load the element at offset two from %A. This should not be promoted!
+        %A.2 = getelementptr i32* %A, i32 2
+        %R = load i32* %A.2
+        ret i32 %R
+}
+
+define i32 @foo() {
+        %X = call i32 @callee(i1 false, i32* null)             ; <i32> [#uses=1]
+        ret i32 %X
+}
+