From 1f4dfbbcb0986e88e86e0b203f4e83eb3d8c48cf Mon Sep 17 00:00:00 2001 From: Benjamin Kramer Date: Wed, 22 Dec 2010 23:17:45 +0000 Subject: DAGCombine add (sext i1), X into sub X, (zext i1) if sext from i1 is illegal. The latter usually compiles into smaller code. example code: unsigned foo(unsigned x, unsigned y) { if (x != 0) y--; return y; } before: _foo: ## @foo cmpl $1, 4(%esp) ## encoding: [0x83,0x7c,0x24,0x04,0x01] sbbl %eax, %eax ## encoding: [0x19,0xc0] notl %eax ## encoding: [0xf7,0xd0] addl 8(%esp), %eax ## encoding: [0x03,0x44,0x24,0x08] ret ## encoding: [0xc3] after: _foo: ## @foo cmpl $1, 4(%esp) ## encoding: [0x83,0x7c,0x24,0x04,0x01] movl 8(%esp), %eax ## encoding: [0x8b,0x44,0x24,0x08] adcl $-1, %eax ## encoding: [0x83,0xd0,0xff] ret ## encoding: [0xc3] llvm-svn: 122455 --- llvm/test/CodeGen/X86/add.ll | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'llvm/test') diff --git a/llvm/test/CodeGen/X86/add.ll b/llvm/test/CodeGen/X86/add.ll index d6e99ee1a7e..3ec5358affb 100644 --- a/llvm/test/CodeGen/X86/add.ll +++ b/llvm/test/CodeGen/X86/add.ll @@ -120,3 +120,15 @@ entry: ; X64: addq ; X64-NEXT: sbbq ; X64-NEXT: testb + +define i32 @test9(i32 %x, i32 %y) nounwind readnone { + %cmp = icmp eq i32 %x, 10 + %sub = sext i1 %cmp to i32 + %cond = add i32 %sub, %y + ret i32 %cond +; X64: test9: +; X64: cmpl $10 +; X64: sete +; X64: subl +; X64: ret +} -- cgit v1.2.3