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| author | Craig Topper <craig.topper@intel.com> | 2018-12-12 19:20:21 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2018-12-12 19:20:21 +0000 |
| commit | 4937adf75f024f5cbd3cc190d5bd57d1761aefc3 (patch) | |
| tree | d7a7794e50161f74cfd6aa0c008d32296392121b /llvm/test/CodeGen/X86/select.ll | |
| parent | 2ef6c46b2f9a2f9dce73d7b15bf837a2feb0bd8a (diff) | |
| download | bcm5719-llvm-4937adf75f024f5cbd3cc190d5bd57d1761aefc3.tar.gz bcm5719-llvm-4937adf75f024f5cbd3cc190d5bd57d1761aefc3.zip | |
[X86] Emit SBB instead of SETCC_CARRY from LowerSELECT. Break false dependency on the SBB input.
I'm hoping we can just replace SETCC_CARRY with SBB. This is another step towards that.
I've explicitly used zero as the input to the setcc to avoid a false dependency that we've had with the SETCC_CARRY. I changed one of the patterns that used NEG to instead use an explicit compare with 0 on the LHS. We needed the zero anyway to avoid the false dependency. The negate would clobber its input register. By using a CMP we can avoid that which could be useful.
Differential Revision: https://reviews.llvm.org/D55414
llvm-svn: 348959
Diffstat (limited to 'llvm/test/CodeGen/X86/select.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/select.ll | 46 |
1 files changed, 16 insertions, 30 deletions
diff --git a/llvm/test/CodeGen/X86/select.ll b/llvm/test/CodeGen/X86/select.ll index f35da3b8b2c..947c9513720 100644 --- a/llvm/test/CodeGen/X86/select.ll +++ b/llvm/test/CodeGen/X86/select.ll @@ -624,21 +624,13 @@ define void @test8(i1 %c, <6 x i32>* %dst.addr, <6 x i32> %src1,<6 x i32> %src2) ;; Test integer select between values and constants. define i64 @test9(i64 %x, i64 %y) nounwind readnone ssp noredzone { -; GENERIC-LABEL: test9: -; GENERIC: ## %bb.0: -; GENERIC-NEXT: cmpq $1, %rdi -; GENERIC-NEXT: sbbq %rax, %rax -; GENERIC-NEXT: orq %rsi, %rax -; GENERIC-NEXT: retq -; -; ATOM-LABEL: test9: -; ATOM: ## %bb.0: -; ATOM-NEXT: cmpq $1, %rdi -; ATOM-NEXT: sbbq %rax, %rax -; ATOM-NEXT: orq %rsi, %rax -; ATOM-NEXT: nop -; ATOM-NEXT: nop -; ATOM-NEXT: retq +; CHECK-LABEL: test9: +; CHECK: ## %bb.0: +; CHECK-NEXT: xorl %eax, %eax +; CHECK-NEXT: cmpq $1, %rdi +; CHECK-NEXT: sbbq %rax, %rax +; CHECK-NEXT: orq %rsi, %rax +; CHECK-NEXT: retq ; ; ATHLON-LABEL: test9: ; ATHLON: ## %bb.0: @@ -672,21 +664,13 @@ define i64 @test9(i64 %x, i64 %y) nounwind readnone ssp noredzone { ;; Same as test9 define i64 @test9a(i64 %x, i64 %y) nounwind readnone ssp noredzone { -; GENERIC-LABEL: test9a: -; GENERIC: ## %bb.0: -; GENERIC-NEXT: cmpq $1, %rdi -; GENERIC-NEXT: sbbq %rax, %rax -; GENERIC-NEXT: orq %rsi, %rax -; GENERIC-NEXT: retq -; -; ATOM-LABEL: test9a: -; ATOM: ## %bb.0: -; ATOM-NEXT: cmpq $1, %rdi -; ATOM-NEXT: sbbq %rax, %rax -; ATOM-NEXT: orq %rsi, %rax -; ATOM-NEXT: nop -; ATOM-NEXT: nop -; ATOM-NEXT: retq +; CHECK-LABEL: test9a: +; CHECK: ## %bb.0: +; CHECK-NEXT: xorl %eax, %eax +; CHECK-NEXT: cmpq $1, %rdi +; CHECK-NEXT: sbbq %rax, %rax +; CHECK-NEXT: orq %rsi, %rax +; CHECK-NEXT: retq ; ; ATHLON-LABEL: test9a: ; ATHLON: ## %bb.0: @@ -803,6 +787,7 @@ define i64 @test10(i64 %x, i64 %y) nounwind readnone ssp noredzone { define i64 @test11(i64 %x, i64 %y) nounwind readnone ssp noredzone { ; CHECK-LABEL: test11: ; CHECK: ## %bb.0: +; CHECK-NEXT: xorl %eax, %eax ; CHECK-NEXT: cmpq $1, %rdi ; CHECK-NEXT: sbbq %rax, %rax ; CHECK-NEXT: notq %rax @@ -842,6 +827,7 @@ define i64 @test11(i64 %x, i64 %y) nounwind readnone ssp noredzone { define i64 @test11a(i64 %x, i64 %y) nounwind readnone ssp noredzone { ; CHECK-LABEL: test11a: ; CHECK: ## %bb.0: +; CHECK-NEXT: xorl %eax, %eax ; CHECK-NEXT: cmpq $1, %rdi ; CHECK-NEXT: sbbq %rax, %rax ; CHECK-NEXT: notq %rax |
