fix a serious pessimization that Tron on IRC pointed out where we would

"boolify" pointers, generating really awful code because getting the pointer
value requires a load itself.  Before:

_foo:
	movb	$1, _X.b
	ret
_get:
	xorl	%ecx, %ecx
	movb	_X.b, %al
	testb	%al, %al
	movl	$_Y, %eax
	cmove	%ecx, %eax
	ret

With the xform disabled:

_foo:
	movl	$_Y, _X
	ret
_get:
	movl	_X, %eax
	ret



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66351 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 0 deletions

diff --git a/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll b/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll
new file mode 100644
index 0000000..8dba5b1
--- /dev/null
+++ b/test/Transforms/GlobalOpt/2009-03-07-PromotePtrToBool.ll
@@ -0,0 +1,17 @@
+; RUN: llvm-as < %s | opt -globalopt | llvm-dis | grep {@X = internal global i32}
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+target triple = "i386-apple-darwin7"
+@X = internal global i32* null		; <i32**> [#uses=2]
+@Y = internal global i32 0		; <i32*> [#uses=1]
+
+define void @foo() nounwind {
+entry:
+	store i32* @Y, i32** @X, align 4
+	ret void
+}
+
+define i32* @get() nounwind {
+entry:
+	%0 = load i32** @X, align 4		; <i32*> [#uses=1]
+	ret i32* %0
+}