Enhance address-mode folding of ISD::ADD to handle cases where the
operands can't both be fully folded at the same time. For example,
in the included testcase, a global variable is being added with
an add of two values. The global variable wants RIP-relative
addressing, so it can't share the address with another base
register, but it's still possible to fold the initial add.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66865 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/fold-add.ll b/test/CodeGen/X86/fold-add.ll
new file mode 100644
index 0000000..2828ad2
--- /dev/null
+++ b/test/CodeGen/X86/fold-add.ll
@@ -0,0 +1,25 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep {cmpb \$0, (%r.\*,%r.\*)}
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-apple-darwin9.6"
+@prev_length = internal global i32 0 ; <i32*> [#uses=1]
+@window = internal global [65536 x i8] zeroinitializer, align 32 ; <[65536 x i8]*> [#uses=1]
+@llvm.used = appending global [1 x i8*] [i8* bitcast (i32 (i32)* @longest_match to i8*)] ; <[1 x i8*]*> [#uses=0]
+
+define fastcc i32 @longest_match(i32 %cur_match) nounwind {
+entry:
+ %0 = load i32* @prev_length, align 4 ; <i32> [#uses=3]
+ %1 = zext i32 %cur_match to i64 ; <i64> [#uses=1]
+ %2 = sext i32 %0 to i64 ; <i64> [#uses=1]
+ %.sum3 = add i64 %1, %2 ; <i64> [#uses=1]
+ %3 = getelementptr [65536 x i8]* @window, i64 0, i64 %.sum3 ; <i8*> [#uses=1]
+ %4 = load i8* %3, align 1 ; <i8> [#uses=1]
+ %5 = icmp eq i8 %4, 0 ; <i1> [#uses=1]
+ br i1 %5, label %bb5, label %bb23
+
+bb5: ; preds = %entry
+ ret i32 %0
+
+bb23: ; preds = %entry
+ ret i32 %0
+}