[PATCH] D23808: [X86][SSE] Add lowering to cvttpd2dq/cvttps2dq for sitofp v2f64/2f32 to 2i32

[Simon Pilgrim via llvm-commits]

RKSimon added inline comments.


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Comment at: test/CodeGen/X86/vec_fp_to_int.ll:102
+; SSE-NEXT:    cvttpd2dq %xmm0, %xmm1
+; SSE-NEXT:    cvttpd2dq %xmm0, %xmm0
 ; SSE-NEXT:    punpcklqdq {{.*#+}} xmm0 = xmm0[0],xmm1[0]
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craig.topper wrote:
> Why does this test case end up with 2 cvttpd2dq instructions that need to be unpacked?
Its demonstrating that we're not propagating the undef nature of the upper <2 x double> from the shuffle in the test. On SSE it results in an unnecessary extra cvttpd2dq and on AVX it results in a vcvttpd2dqy instead of just vcvttpd2dq. Makes a difference on 128-bit ALU Jaguar but is a separate fix from this patch.


Repository:
  rL LLVM

https://reviews.llvm.org/D23808