From badb2d23d1042a991b8c6e31ff19ffd3f6712570 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 13 Aug 2007 20:03:06 +0000
Subject: When x86 addresses matching exceeds its recursion limit, check to see
 if the base register is already occupied before assuming it can be used. This
 fixes bogus code generation in the accompanying testcase.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41049 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/lea-recursion.ll | 47 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 test/CodeGen/X86/lea-recursion.ll

(limited to 'test')

diff --git a/test/CodeGen/X86/lea-recursion.ll b/test/CodeGen/X86/lea-recursion.ll
new file mode 100644
index 0000000..ca7b367
--- /dev/null
+++ b/test/CodeGen/X86/lea-recursion.ll
@@ -0,0 +1,47 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | grep lea | wc -l | grep 12
+
+; This testcase was written to demonstrate an instruction-selection problem,
+; however it also happens to expose a limitation in the DAGCombiner's
+; expression reassociation which causes it to miss opportunities for
+; constant folding due to the intermediate adds having multiple uses.
+; The Reassociate pass has similar limitations. If these limitations are
+; fixed, the test commands above will need to be updated to expect fewer
+; lea instructions.
+
+@g0 = weak global [1000 x i32] zeroinitializer, align 32		; <[1000 x i32]*> [#uses=8]
+@g1 = weak global [1000 x i32] zeroinitializer, align 32		; <[1000 x i32]*> [#uses=7]
+
+define void @foo() {
+entry:
+	%tmp4 = load i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 0)		; <i32> [#uses=1]
+	%tmp8 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 0)		; <i32> [#uses=1]
+	%tmp9 = add i32 %tmp4, 1		; <i32> [#uses=1]
+	%tmp10 = add i32 %tmp9, %tmp8		; <i32> [#uses=2]
+	store i32 %tmp10, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 1)
+	%tmp8.1 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 1)		; <i32> [#uses=1]
+	%tmp9.1 = add i32 %tmp10, 1		; <i32> [#uses=1]
+	%tmp10.1 = add i32 %tmp9.1, %tmp8.1		; <i32> [#uses=2]
+	store i32 %tmp10.1, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 2)
+	%tmp8.2 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 2)		; <i32> [#uses=1]
+	%tmp9.2 = add i32 %tmp10.1, 1		; <i32> [#uses=1]
+	%tmp10.2 = add i32 %tmp9.2, %tmp8.2		; <i32> [#uses=2]
+	store i32 %tmp10.2, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 3)
+	%tmp8.3 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 3)		; <i32> [#uses=1]
+	%tmp9.3 = add i32 %tmp10.2, 1		; <i32> [#uses=1]
+	%tmp10.3 = add i32 %tmp9.3, %tmp8.3		; <i32> [#uses=2]
+	store i32 %tmp10.3, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 4)
+	%tmp8.4 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 4)		; <i32> [#uses=1]
+	%tmp9.4 = add i32 %tmp10.3, 1		; <i32> [#uses=1]
+	%tmp10.4 = add i32 %tmp9.4, %tmp8.4		; <i32> [#uses=2]
+	store i32 %tmp10.4, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 5)
+	%tmp8.5 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 5)		; <i32> [#uses=1]
+	%tmp9.5 = add i32 %tmp10.4, 1		; <i32> [#uses=1]
+	%tmp10.5 = add i32 %tmp9.5, %tmp8.5		; <i32> [#uses=2]
+	store i32 %tmp10.5, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 6)
+	%tmp8.6 = load i32* getelementptr ([1000 x i32]* @g1, i32 0, i32 6)		; <i32> [#uses=1]
+	%tmp9.6 = add i32 %tmp10.5, 1		; <i32> [#uses=1]
+	%tmp10.6 = add i32 %tmp9.6, %tmp8.6		; <i32> [#uses=1]
+	store i32 %tmp10.6, i32* getelementptr ([1000 x i32]* @g0, i32 0, i32 7)
+	ret void
+}
+
-- 
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