From 0a9481f44fe4fc76e59109992940a76b2a3f9b3b Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 13 Feb 2011 22:25:43 +0000 Subject: Enhance ComputeMaskedBits to know that aligned frameindexes have their low bits set to zero. This allows us to optimize out explicit stack alignment code like in stack-align.ll:test4 when it is redundant. Doing this causes the code generator to start turning FI+cst into FI|cst all over the place, which is general goodness (that is the canonical form) except that various pieces of the code generator don't handle OR aggressively. Fix this by introducing a new SelectionDAG::isBaseWithConstantOffset predicate, and using it in places that are looking for ADD(X,CST). The ARM backend in particular was missing a lot of addressing mode folding opportunities around OR. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125470 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/CodeGen/X86/stack-align.ll | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'test/CodeGen/X86/stack-align.ll') diff --git a/test/CodeGen/X86/stack-align.ll b/test/CodeGen/X86/stack-align.ll index 8ca0b12b54..793c026712 100644 --- a/test/CodeGen/X86/stack-align.ll +++ b/test/CodeGen/X86/stack-align.ll @@ -7,7 +7,7 @@ target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f3 target triple = "i686-apple-darwin8" @G = external global double -define void @test({ double, double }* byval %z, double* %P) { +define void @test({ double, double }* byval %z, double* %P) nounwind { entry: %tmp3 = load double* @G, align 16 ; [#uses=1] %tmp4 = tail call double @fabs( double %tmp3 ) ; [#uses=1] @@ -21,14 +21,14 @@ entry: ret void } -define void @test2() alignstack(16) { +define void @test2() alignstack(16) nounwind { entry: ; CHECK: andl{{.*}}$-16, %esp ret void } ; Use a call to force a spill. -define <2 x double> @test3(<2 x double> %x, <2 x double> %y) alignstack(32) { +define <2 x double> @test3(<2 x double> %x, <2 x double> %y) alignstack(32) nounwind { entry: ; CHECK: andl{{.*}}$-32, %esp call void @test2() @@ -38,3 +38,14 @@ entry: declare double @fabs(double) +; The pointer is already known aligned, so and x,-16 is eliminable. +define i32 @test4() nounwind { +entry: + %buffer = alloca [2048 x i8], align 16 + %0 = ptrtoint [2048 x i8]* %buffer to i32 + %and = and i32 %0, -16 + ret i32 %and +; CHECK: test4: +; CHECK-NOT: and +; CHECK: ret +} -- cgit v1.2.3