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authorChris Lattner <sabre@nondot.org>2009-11-26 16:26:43 +0000
committerChris Lattner <sabre@nondot.org>2009-11-26 16:26:43 +0000
commit5d5261c819fa2a203dc8d09c7bb71e041a12cd69 (patch)
treec5c1b47626ed98d5afe1bf01616fb4a2aceccc9a /test/Analysis
parentf6ac4d9dadaa62959e04a0281e3bc5f4270fc260 (diff)
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Teach basicaa that x|c == x+c when the c bits of x are clear. This
allows us to compile the example in readme.txt into: LBB1_1: ## %bb movl 4(%rdx,%rax), %ecx movl %ecx, %esi imull (%rdx,%rax), %esi imull %esi, %ecx movl %esi, 8(%rdx,%rax) imull %ecx, %esi movl %ecx, 12(%rdx,%rax) movl %esi, 16(%rdx,%rax) imull %ecx, %esi movl %esi, 20(%rdx,%rax) addq $16, %rax cmpq $4000, %rax jne LBB1_1 instead of: LBB1_1: movl (%rdx,%rax), %ecx imull 4(%rdx,%rax), %ecx movl %ecx, 8(%rdx,%rax) imull 4(%rdx,%rax), %ecx movl %ecx, 12(%rdx,%rax) imull 8(%rdx,%rax), %ecx movl %ecx, 16(%rdx,%rax) imull 12(%rdx,%rax), %ecx movl %ecx, 20(%rdx,%rax) addq $16, %rax cmpq $4000, %rax jne LBB1_1 GCC (4.2) doesn't seem to be able to eliminate the loads in this testcase either, it generates: L2: movl (%rdx), %eax imull 4(%rdx), %eax movl %eax, 8(%rdx) imull 4(%rdx), %eax movl %eax, 12(%rdx) imull 8(%rdx), %eax movl %eax, 16(%rdx) imull 12(%rdx), %eax movl %eax, 20(%rdx) addl $4, %ecx addq $16, %rdx cmpl $1002, %ecx jne L2 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89952 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Analysis')
-rw-r--r--test/Analysis/BasicAA/gep-alias.ll14
1 files changed, 14 insertions, 0 deletions
diff --git a/test/Analysis/BasicAA/gep-alias.ll b/test/Analysis/BasicAA/gep-alias.ll
index 0c5f7ac..320c990 100644
--- a/test/Analysis/BasicAA/gep-alias.ll
+++ b/test/Analysis/BasicAA/gep-alias.ll
@@ -86,4 +86,18 @@ define i32 @test5(i32* %p, i64 %i) {
; CHECK: ret i32 0
}
+; P[i] != p[(i*4)|1]
+define i32 @test6(i32* %p, i64 %i1) {
+ %i = shl i64 %i1, 2
+ %pi = getelementptr i32* %p, i64 %i
+ %i.next = or i64 %i, 1
+ %pi.next = getelementptr i32* %p, i64 %i.next
+ %x = load i32* %pi
+ store i32 42, i32* %pi.next
+ %y = load i32* %pi
+ %z = sub i32 %x, %y
+ ret i32 %z
+; CHECK: @test6
+; CHECK: ret i32 0
+}