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author | Chris Lattner <sabre@nondot.org> | 2010-08-27 18:31:05 +0000 |
---|---|---|
committer | Chris Lattner <sabre@nondot.org> | 2010-08-27 18:31:05 +0000 |
commit | 784f333aef929fbc5867ce17a165837401378c17 (patch) | |
tree | 020c077d0e8e41efaed5555915c4342fcad712ac /test/Transforms | |
parent | 7a9ef44b3b4ddd2dd9a7f92fc8b46c5e5bed6a81 (diff) | |
download | external_llvm-784f333aef929fbc5867ce17a165837401378c17.zip external_llvm-784f333aef929fbc5867ce17a165837401378c17.tar.gz external_llvm-784f333aef929fbc5867ce17a165837401378c17.tar.bz2 |
Add an instcombine to clean up a common pattern produced
by the SRoA "promote to large integer" code, eliminating
some type conversions like this:
%94 = zext i16 %93 to i32 ; <i32> [#uses=2]
%96 = lshr i32 %94, 8 ; <i32> [#uses=1]
%101 = trunc i32 %96 to i8 ; <i8> [#uses=1]
This also unblocks other xforms from happening, now clang is able to compile:
struct S { float A, B, C, D; };
float foo(struct S A) { return A.A + A.B+A.C+A.D; }
into:
_foo: ## @foo
## BB#0: ## %entry
pshufd $1, %xmm0, %xmm2
addss %xmm0, %xmm2
movdqa %xmm1, %xmm3
addss %xmm2, %xmm3
pshufd $1, %xmm1, %xmm0
addss %xmm3, %xmm0
ret
on x86-64, instead of:
_foo: ## @foo
## BB#0: ## %entry
movd %xmm0, %rax
shrq $32, %rax
movd %eax, %xmm2
addss %xmm0, %xmm2
movapd %xmm1, %xmm3
addss %xmm2, %xmm3
movd %xmm1, %rax
shrq $32, %rax
movd %eax, %xmm0
addss %xmm3, %xmm0
ret
This seems pretty close to optimal to me, at least without
using horizontal adds. This also triggers in lots of other
code, including SPEC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112278 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms')
-rw-r--r-- | test/Transforms/InstCombine/trunc.ll | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/test/Transforms/InstCombine/trunc.ll b/test/Transforms/InstCombine/trunc.ll index 2fa5d37..5cb3474 100644 --- a/test/Transforms/InstCombine/trunc.ll +++ b/test/Transforms/InstCombine/trunc.ll @@ -48,3 +48,35 @@ define i64 @test4(i64 %a) { ; CHECK: %d = xor i64 {{.*}}, 8 ; CHECK: ret i64 %d } + +define i32 @test5(i32 %A) { + %B = zext i32 %A to i128 + %C = lshr i128 %B, 16 + %D = trunc i128 %C to i32 + ret i32 %D +; CHECK: @test5 +; CHECK: %C = lshr i32 %A, 16 +; CHECK: ret i32 %C +} + +define i32 @test6(i64 %A) { + %B = zext i64 %A to i128 + %C = lshr i128 %B, 32 + %D = trunc i128 %C to i32 + ret i32 %D +; CHECK: @test6 +; CHECK: %C = lshr i64 %A, 32 +; CHECK: %D = trunc i64 %C to i32 +; CHECK: ret i32 %D +} + +define i92 @test7(i64 %A) { + %B = zext i64 %A to i128 + %C = lshr i128 %B, 32 + %D = trunc i128 %C to i92 + ret i92 %D +; CHECK: @test7 +; CHECK: %C = lshr i64 %A, 32 +; CHECK: %D = zext i64 %C to i92 +; CHECK: ret i92 %D +}
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